Cavitation: Difference between revisions

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{{expert needed|Physics|date=July 2023|reason=Several usages of the term appear to be mixed up|talk=Meaning and scope}}

[[File:Cavitation.jpg|thumb|upright=1|Cavitation damage on a valve plate for an [[Axial piston pump|axial piston]] [[hydraulic pump]]]]

[[File:Cavitation in a gear pump.ogv|thumb|upright=1|This video shows cavitation in a [[gear pump]]]]

[[File:Cavitation Propeller Damage.JPG|right|thumb|upright=1|Cavitation damage evident on the propeller of a personal watercraft]]

'''Cavitation''' in [[fluid mechanics]] and engineering normally is the phenomenon in which the static [[pressure]] of a liquid reduces to below the liquid's [[vapor pressure]], leading to the formation of small vapor-filled cavities in the liquid.<ref>{{cite web | url=https://metro.co.uk/2019/04/18/us-navy-secretly-designed-super-fast-futuristic-aircraft-resembling-ufo-documents-reveal-9246755/ | title=The US Navy secretly designed a super-fast futuristic aircraft resembling a UFO | date=April 18, 2019 }}</ref> When subjected to higher pressure, these cavities, called "bubbles" or "voids", collapse and can generate [[shock wave]]s that may damage machinery. These shock waves are strong when they are very close to the imploded bubble, but rapidly weaken as they propagate away from the implosion. Cavitation is a significant cause of wear in some [[engineering]] contexts. Collapsing voids that implode near to a ~~metal~~ surface cause [[cyclic stress]] through repeated implosion. This results in surface fatigue of the ~~metal~~, causing a type of ~~wear~~ also called "cavitation". The most common examples of this kind of wear are to pump [[impeller]]s, and bends where a sudden change in the direction of liquid occurs.

'''Cavitation''' in [[fluid mechanics]] and engineering normally is the phenomenon in which the static [[pressure]] of a liquid reduces to below the liquid's [[vapor pressure]], leading to the formation of small vapor-filled cavities in the liquid.<ref>{{cite web | url=https://metro.co.uk/2019/04/18/us-navy-secretly-designed-super-fast-futuristic-aircraft-resembling-ufo-documents-reveal-9246755/ | title=The US Navy secretly designed a super-fast futuristic aircraft resembling a UFO | date=April 18, 2019 }}</ref> When subjected to higher pressure, these cavities, called "bubbles" or "voids", collapse and can generate [[shock wave]]s that may damage machinery. As a concrete [[propeller]] example: The pressure on the suction side of the propeller blades can be very low and when the pressure falls to that of the vapour pressure of the working liquid, cavities filled with gas vapour can form. The process of the formation of these cavities is referred to as cavitation. If the cavities move into the regions of higher pressure (lower velocity), they will implode or collapse. These shock waves are strong when they are very close to the imploded bubble, but rapidly weaken as they propagate away from the implosion. Cavitation collapse is therefore a significant cause of wear in some [[engineering]] contexts. Collapsing voids that implode near to a hard surface cause [[cyclic stress]] through repeated implosion. This results in surface fatigue of the material, causing a type of damage also called "cavitation damage" or "cavitation erosion". The most common examples of this kind of wear are to pump [[impeller]]s, and pipe bends where a sudden change in the direction of fast moving liquid occurs.

Cavitation is usually divided into two classes of behavior. ''Inertial (or transient) cavitation'' is the process in which a void or bubble in a liquid rapidly collapses, producing a [[shock wave]]. It occurs in nature in the strikes of [[mantis shrimp]] and [[pistol shrimp]], as well as in the [[vascular tissue]]s of plants. In manufactured objects, it can occur in [[control valves]], [[pump]]s, [[propeller]]s and [[impeller]]s.<ref>{{cite journal | doi=10.3390/fluids5040243 | doi-access=free | title=Impact of Leading Edge Roughness in Cavitation Simulations around a Twisted Foil | date=2020 | last1=Asnaghi | first1=Abolfazl | last2=Bensow | first2=Rickard E. | journal=Fluids | volume=5 | issue=4 | page=243 | bibcode=2020Fluid...5..243A }}</ref><ref>{{Cite journal |last=Paun, Viorel-Puiu & Patrascoiu, Constantin |date=2010-01-03 |title=Ideal Cavitation Erosion Process and Characteristic Erosion Curves. |url=https://www.researchgate.net/publication/356503796 |journal=Revista de Chimie -Bucharest- Original Edition |volume=61 |issue=3 |~~pages~~=281 |via=Research Gate}}</ref>

Cavitation is usually divided into two classes of behavior. ''Inertial (or transient) cavitation'' is the process in which a void or bubble in a liquid rapidly collapses, producing a [[shock wave]]. It occurs in nature in the strikes of [[mantis shrimp]] and [[pistol shrimp]], as well as in the [[vascular tissue]]s of plants. In manufactured objects, it can occur in [[control valves]], [[pump]]s, [[propeller]]s and [[impeller]]s.<ref>{{cite journal | doi=10.3390/fluids5040243 | doi-access=free | title=Impact of Leading Edge Roughness in Cavitation Simulations around a Twisted Foil | date=2020 | last1=Asnaghi | first1=Abolfazl | last2=Bensow | first2=Rickard E. | journal=Fluids | volume=5 | issue=4 | page=243 | bibcode=2020Fluid...5..243A }}</ref><ref>{{Cite journal |last=Paun, Viorel-Puiu & Patrascoiu, Constantin |date=2010-01-03 |title=Ideal Cavitation Erosion Process and Characteristic Erosion Curves. |url=https://www.researchgate.net/publication/356503796 |journal=Revista de Chimie -Bucharest- Original Edition |volume=61 |issue=3 |page=281 |via=Research Gate}}</ref>

''Non-inertial cavitation'' is the process in which a bubble in a fluid is forced to oscillate in size or shape due to some form of energy input, such as an [[Sound|acoustic field]]. The gas in the bubble may contain a portion of a different gas than the vapor phase of the liquid. Such cavitation is often employed in [[ultrasonic cleaning]] baths and can also be observed in pumps, propellers, etc.

Since the shock waves formed by collapse of the voids are strong enough to cause significant damage to parts, cavitation is typically an undesirable phenomenon in machinery. It may be desirable if intentionally used, for example, to sterilize contaminated surgical instruments, break down pollutants in water purification systems, [[emulsify]] tissue for cataract surgery or kidney stone [[lithotripsy]], or [[homogenize]] fluids. It is very often specifically prevented in the design of machines such as turbines or propellers, and eliminating cavitation is a major field in the study of [[fluid dynamics]]. However, it is sometimes useful and does not cause damage when the bubbles collapse away from machinery, such as in [[supercavitation]].

Since the shock waves formed by collapse of the voids are strong enough to cause significant damage to parts, cavitation is typically an undesirable phenomenon in machinery. It may be desirable if intentionally used, for example, to sterilize contaminated surgical instruments, break down pollutants in water purification systems, [[emulsify]] tissue for cataract surgery or kidney stone [[lithotripsy]], or [[homogenize]] fluids. It is very often specifically prevented in the design of machines such as turbines or propellers, and eliminating cavitation is a major field in the study of [[fluid dynamics]]. However, it is sometimes useful and does not cause damage when the bubbles collapse away from machinery surfaces, such as in [[supercavitation]].

== Physics ==

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[[Vapor]] gases evaporate into the cavity from the surrounding medium; thus, the cavity is not a vacuum at all, but rather a low-pressure vapor (gas) bubble. Once the conditions which caused the bubble to form are no longer present, such as when the bubble moves downstream, the surrounding liquid begins to implode due its higher pressure, building up momentum as it moves inward. As the bubble finally collapses, the inward momentum of the surrounding liquid causes a sharp increase of pressure and temperature of the vapor within. The bubble eventually collapses to a minute fraction of its original size, at which point the gas within dissipates into the surrounding liquid via a rather violent mechanism which releases a significant amount of energy in the form of an acoustic shock wave and as [[sonoluminescence|visible light]]. At the point of total collapse, the temperature of the vapor within the bubble may be several thousand [[Kelvin]], and the pressure several hundred atmospheres.<ref>{{cite journal|journal=Environmental Health Perspectives|volume=64|pages=233–252|date=1985|title=Free radical generation by ultrasound in aqueous and nonaqueous solutions|last1=Riesz|first1=P.|first2=D.|last2=Berdahl|first3=C.L.|last3=Christman|pmc=1568618|doi=10.2307/3430013|pmid=3007091|jstor=3430013}}</ref>

The physical process of cavitation inception is similar to [[boiling]]. The major difference between the two is the [[thermodynamic]] paths that precede the formation of the vapor. Boiling occurs when the local temperature of the liquid reaches the [[saturation temperature]], and further heat is supplied to allow the liquid to sufficiently [[phase transition|phase change]] into a gas. Cavitation inception occurs when the local pressure falls sufficiently far below the saturated vapor pressure, a value given by the tensile strength of the liquid at a certain temperature.<ref>{{cite web|last1=Brennen|first1=Christopher |title=Cavitation and Bubble Dynamics|publisher=Oxford University Press|~~pages~~=21 |url=http://authors.library.caltech.edu/25017/1/cavbubdynam.pdf |archive-url=https://web.archive.org/web/20121004094948/http://authors.library.caltech.edu/25017/1/cavbubdynam.pdf |archive-date=2012-10-04 |url-status=live|access-date=27 February 2015}}</ref>

The physical process of cavitation inception is similar to [[boiling]]. The major difference between the two is the [[thermodynamic]] paths that precede the formation of the vapor. Boiling occurs when the local temperature of the liquid reaches the [[saturation temperature]], and further heat is supplied to allow the liquid to sufficiently [[phase transition|phase change]] into a gas. Cavitation inception occurs when the local pressure falls sufficiently far below the saturated vapor pressure, a value given by the tensile strength of the liquid at a certain temperature.<ref>{{cite web|last1=Brennen|first1=Christopher |title=Cavitation and Bubble Dynamics|publisher=Oxford University Press|page=21 |url=http://authors.library.caltech.edu/25017/1/cavbubdynam.pdf |archive-url=https://web.archive.org/web/20121004094948/http://authors.library.caltech.edu/25017/1/cavbubdynam.pdf |archive-date=2012-10-04 |url-status=live|access-date=27 February 2015}}</ref>

In order for cavitation inception to occur, the cavitation "bubbles" generally need a surface on which they can [[nucleation|nucleate]]. This surface can be provided by the sides of a container, by [[impurity|impurities]] in the liquid, or by small undissolved microbubbles within the liquid. It is generally accepted that [[hydrophobe|hydrophobic]] surfaces stabilize small bubbles. These pre-existing bubbles start to grow unbounded when they are exposed to a pressure below the threshold pressure, termed Blake's threshold.<ref>{{cite book|vauthors=Postema M, de Jong N, Schmitz G|title=IEEE Ultrasonics Symposium, 2005 |chapter=Shell rupture threshold, fragmentation threshold, blake threshold |date=Sep 2005|volume=3 |location=Rotterdam, Netherlands|pages=1708–1711|doi=10.1109/ULTSYM.2005.1603194|isbn=0-7803-9382-1 |s2cid=5683516 |chapter-url=https://hal.archives-ouvertes.fr/hal-03193373/document}}</ref> The presence of an incompressible core inside a cavitation nucleus substantially lowers the cavitation threshold below the Blake threshold.<ref>{{cite journal|vauthors=Carlson CS, Matsumoto R, Fushino K, Shinzato M, Kudo N, Postema M|title=Nucleation threshold of carbon black ultrasound contrast agent|journal=Japanese Journal of Applied Physics|year=2021|volume=60|issue=SD|pages=SDDA06|doi=10.35848/1347-4065/abef0f|bibcode=2021JaJAP..60DDA06C |s2cid=233539493 |url=https://hal.archives-ouvertes.fr/hal-03192654/document|doi-access=free}}</ref>

In order for cavitation inception to occur, the cavitation "bubbles" generally need a surface on which they can [[nucleation|nucleate]]. This surface can be provided by the sides of a container, by [[impurity|impurities]] in the liquid, or by small undissolved microbubbles within the liquid. It is generally accepted that [[hydrophobe|hydrophobic]] surfaces stabilize small bubbles. These pre-existing bubbles start to grow unbounded when they are exposed to a pressure below the threshold pressure, termed Blake's threshold.<ref>{{cite book|vauthors=Postema M, de Jong N, Schmitz G|title=IEEE Ultrasonics Symposium, 2005 |chapter=Shell rupture threshold, fragmentation threshold, blake threshold |date=Sep 2005|volume=3 |location=Rotterdam, Netherlands|pages=1708–1711|doi=10.1109/ULTSYM.2005.1603194|isbn=0-7803-9382-1 |s2cid=5683516 |url=https://hal.science/hal-03193373 |chapter-url=https://hal.archives-ouvertes.fr/hal-03193373/document}}</ref> The presence of an incompressible core inside a cavitation nucleus substantially lowers the cavitation threshold below the Blake threshold.<ref>{{cite journal|vauthors=Carlson CS, Matsumoto R, Fushino K, Shinzato M, Kudo N, Postema M|title=Nucleation threshold of carbon black ultrasound contrast agent|journal=Japanese Journal of Applied Physics|year=2021|volume=60|issue=SD|pages=SDDA06|doi=10.35848/1347-4065/abef0f|bibcode=2021JaJAP..60DDA06C |s2cid=233539493 |url=https://hal.archives-ouvertes.fr/hal-03192654/document|doi-access=free}}</ref>

The vapor pressure here differs from the meteorological definition of vapor pressure, which describes the partial pressure of water in the atmosphere at some value less than 100% saturation. Vapor pressure as relating to cavitation refers to the vapor pressure in equilibrium conditions and can therefore be more accurately defined as the equilibrium (or saturated) [[vapor pressure]].

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===Hydrodynamic cavitation===

Hydrodynamic cavitation is the process of vaporisation, bubble generation and bubble implosion which occurs in a flowing liquid as a result of a decrease and subsequent increase in local pressure. Cavitation will only occur if the local pressure declines to some point below the saturated [[vapor pressure]] of the liquid and subsequent recovery above the vapor pressure. If the recovery pressure is not above the vapor pressure then flashing is said to have occurred. In pipe systems, cavitation typically occurs either as the result of an increase in the kinetic energy (through an area constriction) or an increase in the pipe elevation.

Hydrodynamic cavitation is the process of vaporisation, bubble generation and bubble implosion which occurs in a flowing liquid as a result of a decrease and subsequent increase in local pressure. Cavitation will only occur if the local pressure declines to some point below the saturated [[vapor pressure]] of the liquid and subsequent recovery above the vapor pressure. If the recovery pressure is not above the vapor pressure then flashing is said to have occurred.{{cn|date=September 2025}}{{clarify|how is this cavitation?|date=September 2025}} In pipe systems, cavitation typically occurs either as the result of an increase in the kinetic energy (through an area constriction) or an increase in the pipe elevation.

Hydrodynamic cavitation can be produced by passing a liquid through a constricted channel at a specific [[flow velocity]] or by mechanical rotation of an object through a liquid. In the case of the constricted channel and based on the specific (or unique) geometry of the system, the combination of pressure and kinetic energy can create the hydrodynamic cavitation cavern downstream of the local constriction generating high energy cavitation bubbles.

Hydrodynamic cavitation can be produced by passing a liquid through a constricted channel at a specific [[flow velocity]] or by mechanical rotation{{clarify|Why specifically rotation?|date=September 2025}} of an object through a liquid. In the case of the constricted channel and based on the specific (or unique) geometry of the system, the combination of pressure and kinetic energy can create the hydrodynamic cavitation cavern downstream of the local constriction generating high energy cavitation bubbles.

Based on the thermodynamic phase change diagram, an increase in temperature could initiate a known phase change mechanism known as boiling. However, a decrease in static pressure could also help one pass the multi-phase diagram and initiate another phase change mechanism known as cavitation. On the other hand, a local increase in flow velocity could lead to a static pressure drop to the critical point at which cavitation could be initiated (based on Bernoulli's principle). The critical pressure point is vapor saturated pressure. In a closed fluidic system where no flow leakage is detected, a decrease in cross-sectional area would lead to velocity increment and hence static pressure drop. This is the working principle of many hydrodynamic cavitation based reactors for different applications such as water treatment, energy harvesting, heat transfer enhancement, food processing, etc.<ref>{{Cite journal |last1=Gevari|first1=Moein Talebian|last2=Abbasiasl|first2=Taher|last3=Niazi|first3=Soroush|last4=Ghorbani |first4=Morteza|last5=Koşar|first5=Ali|date=2020-05-05|title=Direct and indirect thermal applications of hydrodynamic and acoustic cavitation: A review|journal=Applied Thermal Engineering|volume=171|~~pages~~=115065 |doi=10.1016/j.applthermaleng.2020.115065|bibcode=2020AppTE.17115065G |s2cid=214446752|issn=1359-4311}}</ref>

Based on the thermodynamic phase change diagram, an increase in temperature could initiate a known phase change mechanism known as boiling. However, a decrease in static pressure could also help one pass the multi-phase diagram{{clarify|"pass the multi-phase diagram"? what does this mean?, and who is the one it helps?|date=September 2025}} and initiate another phase change mechanism known as cavitation. On the other hand, a local increase in flow velocity could lead to a static pressure drop to the critical point at which cavitation could be initiated (based on Bernoulli's principle). The critical pressure point is vapor saturated pressure. In a closed fluidic system where no flow leakage is detected, a decrease in cross-sectional area would lead to velocity increment and hence static pressure drop. This is the working principle of many hydrodynamic cavitation based reactors for different applications such as water treatment, energy harvesting, heat transfer enhancement, food processing, etc.<ref>{{Cite journal |last1=Gevari|first1=Moein Talebian|last2=Abbasiasl|first2=Taher|last3=Niazi|first3=Soroush|last4=Ghorbani |first4=Morteza|last5=Koşar|first5=Ali|date=2020-05-05|title=Direct and indirect thermal applications of hydrodynamic and acoustic cavitation: A review|journal=Applied Thermal Engineering|volume=171|article-number=115065 |doi=10.1016/j.applthermaleng.2020.115065|bibcode=2020AppTE.17115065G |s2cid=214446752|issn=1359-4311}}</ref>

There are different flow patterns detected as a cavitation flow progresses: inception, developed flow, supercavitation, and choked flow. Inception is the first moment that the second phase (gas phase) appears in the system. This is the weakest cavitating flow captured in a system corresponding to the highest [[cavitation number]]. When the cavities grow and becomes larger in size in the orifice or venturi structures, developed flow is recorded. The most intense cavitating flow is known as supercavitation where theoretically all the nozzle area of an orifice is filled with gas bubbles. This flow regime corresponds to the lowest cavitation number in a system. After supercavitation, the system is not capable of passing more flow. Hence, velocity does not change while the upstream pressure increase. This would lead to an increase in cavitation number which shows that choked flow occurred.<ref>{{Cite journal |last1=Gevari|first1=Moein Talebian|last2=Shafaghi|first2=Ali Hosseinpour|last3=Villanueva|first3=Luis Guillermo|last4=Ghorbani |first4=Morteza|last5=Koşar|first5=Ali|date=January 2020|title=Engineered Lateral Roughness Element Implementation and Working Fluid Alteration to Intensify Hydrodynamic Cavitating Flows on a Chip for Energy Harvesting|journal=Micromachines|volume=11|issue=1|~~pages~~=49|doi=10.3390/mi11010049|pmid=31906037|pmc=7019874|doi-access=free}}</ref>

There are different flow patterns detected as a cavitation flow progresses: inception, developed flow, supercavitation, and choked flow. Inception is the first moment that the second phase (gas phase) appears in the system. This is the weakest cavitating flow captured in a system corresponding to the highest [[cavitation number]]. When the cavities grow and becomes larger in size in the orifice or venturi structures, developed flow is recorded. The most intense cavitating flow is known as supercavitation where theoretically all the nozzle area of an orifice is filled with gas bubbles. This flow regime corresponds to the lowest cavitation number in a system. After supercavitation, the system is not capable of passing more flow. Hence, velocity does not change while the upstream pressure increase. This would lead to an increase in cavitation number which shows that choked flow occurred.<ref>{{Cite journal |last1=Gevari|first1=Moein Talebian|last2=Shafaghi|first2=Ali Hosseinpour|last3=Villanueva|first3=Luis Guillermo|last4=Ghorbani |first4=Morteza|last5=Koşar|first5=Ali|date=January 2020|title=Engineered Lateral Roughness Element Implementation and Working Fluid Alteration to Intensify Hydrodynamic Cavitating Flows on a Chip for Energy Harvesting|journal=Micromachines|volume=11|issue=1|page=49|doi=10.3390/mi11010049|pmid=31906037|pmc=7019874|doi-access=free}}</ref>

The process of bubble generation, and the subsequent growth and collapse of the cavitation bubbles, results in very high energy densities and in very high local temperatures and local pressures at the surface of the bubbles for a very short time. The overall liquid medium environment, therefore, remains at ambient conditions. When uncontrolled, cavitation is damaging; by controlling the flow of the cavitation, however, the power can be harnessed and non-destructive. Controlled cavitation can be used to enhance chemical reactions or propagate certain unexpected reactions because free radicals are generated in the process due to disassociation of vapors trapped in the cavitating bubbles.<ref>{{cite web |last1=STOPAR |first1=DAVID |title=HYDRODYNAMIC CAVITATION |url=https://davidstopar.wixsite.com/home/hydrodynamic-cavitation |access-date=17 January 2020}}</ref>

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Orifices and venturi are reported to be widely used for generating cavitation. A venturi has an inherent advantage over an orifice because of its smooth converging and diverging sections, such that it can generate a higher flow velocity at the throat for a given pressure drop across it. On the other hand, an orifice has an advantage that it can accommodate a greater number of holes (larger perimeter of holes) in a given cross sectional area of the pipe.<ref>{{cite journal |first1=Vijayanand S. |last1=Moholkar |first2=Aniruddha B. |last2=Pandit |doi=10.1002/aic.690430628 |year=1997 |title=Bubble Behavior in Hydrodynamic Cavitation: Effect of Turbulence |journal=AIChE Journal |volume=43 |issue=6 |pages=1641–1648 |bibcode=1997AIChE..43.1641M }}</ref>

The cavitation phenomenon can be controlled to enhance the performance of high-speed marine vessels and projectiles, as well as in material processing technologies, in medicine, etc. Controlling the cavitating flows in liquids can be achieved only by advancing the mathematical foundation of the cavitation processes. These processes are manifested in different ways, the most common ones and promising for control being bubble cavitation and supercavitation. The first exact classical solution should perhaps be credited to the well-known solution by [[Hermann von Helmholtz]] in 1868.<ref>{{cite journal |last1=Helmholtz |first1=Hermann von |title=Über diskontinuierliche Flüssigkeits-Bewegungen |journal=Monatsberichte der Königlichen Preussische Akademie des Wissenschaften zu Berlin (Monthly Reports of the Royal Prussian Academy of Sciences at Berlin) |date=1868 |volume=23 |pages=215–228 |url=https://www.biodiversitylibrary.org/item/111036#page/223/mode/1up |trans-title=On discontinuous motions of fluids |language=de}}</ref> The earliest distinguished studies of academic type on the theory of a cavitating flow with free boundaries and supercavitation were published in the book ''Jets, wakes and cavities''<ref>Birkhoff, G, Zarantonello. E (1957) Jets, wakes and cavities. New York: Academic Press. 406p.</ref> followed by ''Theory of jets of ideal fluid''.<ref>Gurevich, MI (1978) Theory of jets of ideal fluid. Nauka, Moscow, 536p. (in Russian)</ref> Widely used in these books was the well-developed theory of conformal mappings of functions of a complex variable, allowing one to derive a large number of exact solutions of plane problems. Another venue combining the existing exact solutions with approximated and heuristic models was explored in the work ''Hydrodynamics of Flows with Free Boundaries''<ref>Logvinovich, GV (1969) Hydrodynamics of Flows with Free Boundaries. Naukova dumka, Kiev, 215p. (In Russian)</ref> that refined the applied calculation techniques based on the principle of cavity expansion independence, theory of pulsations and stability of elongated axisymmetric cavities, etc.<ref>Knapp, RT, Daili, JW, Hammit, FG (1970) Cavitation. New York: Mc Graw Hill Book Company. 578p.</ref> and in ''Dimensionality and similarity methods in the problems of the hydromechanics of vessels''.<ref>Epshtein, LA (1970) Dimensionality and similarity methods in the problems of the hydromechanics of vessels. Sudostroyenie, Leningrad, 208p. (In Russian)</ref>

The cavitation phenomenon can be controlled to enhance the performance of high-speed marine vessels and projectiles, as well as in material processing technologies, in medicine, etc. Controlling the cavitating flows in liquids can be achieved only by advancing the mathematical foundation of the cavitation processes. These processes are manifested in different ways, the most common ones and promising for control being bubble cavitation and supercavitation. The first exact classical solution should perhaps be credited to the well-known solution by [[Hermann von Helmholtz]] in 1868.<ref>{{cite journal |last1=Helmholtz |first1=Hermann von |title=Über diskontinuierliche Flüssigkeits-Bewegungen |journal=Monatsberichte der Königlichen Preussische Akademie des Wissenschaften zu Berlin (Monthly Reports of the Royal Prussian Academy of Sciences at Berlin) |date=1868 |volume=23 |pages=215–228 |url=https://www.biodiversitylibrary.org/item/111036#page/223/mode/1up |trans-title=On discontinuous motions of fluids |language=de}}</ref> The earliest distinguished studies of academic type on the theory of a cavitating flow with free boundaries and supercavitation were published in the book ''Jets, wakes and cavities''<ref>[[Garrett Birkhoff|Birkhoff, G]], Zarantonello. E (1957) Jets, wakes and cavities. New York: Academic Press. 406p.</ref> followed by ''Theory of jets of ideal fluid''.<ref>Gurevich, MI (1978) Theory of jets of ideal fluid. Nauka, Moscow, 536p. (in Russian)</ref> Widely used in these books was the well-developed theory of conformal mappings of functions of a complex variable, allowing one to derive a large number of exact solutions of plane problems. Another venue combining the existing exact solutions with approximated and heuristic models was explored in the work ''Hydrodynamics of Flows with Free Boundaries''<ref>Logvinovich, GV (1969) Hydrodynamics of Flows with Free Boundaries. Naukova dumka, Kiev, 215p. (In Russian)</ref> that refined the applied calculation techniques based on the principle of cavity expansion independence, theory of pulsations and stability of elongated axisymmetric cavities, etc.<ref>Knapp, RT, Daili, JW, Hammit, FG (1970) Cavitation. New York: Mc Graw Hill Book Company. 578p.</ref> and in ''Dimensionality and similarity methods in the problems of the hydromechanics of vessels''.<ref>Epshtein, LA (1970) Dimensionality and similarity methods in the problems of the hydromechanics of vessels. Sudostroyenie, Leningrad, 208p. (In Russian)</ref>

A natural continuation of these studies was recently presented in ''The Hydrodynamics of Cavitating Flows''<ref>Terentiev, A, Kirschner, I, Uhlman, J, (2011) The Hydrodynamics of Cavitating Flows. Backbone Publishing Company, 598pp.</ref> – an encyclopedic work encompassing all the best advances in this domain for the last three decades, and blending the classical methods of mathematical research with the modern capabilities of computer technologies. These include elaboration of nonlinear numerical methods of solving 3D cavitation problems, refinement of the known plane linear theories, development of asymptotic theories of axisymmetric and nearly axisymmetric flows, etc. As compared to the classical approaches, the new trend is characterized by expansion of the theory into the 3D flows. It also reflects a certain correlation with current works of an applied character on the hydrodynamics of supercavitating bodies.

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Ultrasonic cavitation inception will occur when the acceleration of the ultrasound source is enough to produce the needed pressure drop. This pressure drop depends on the value of the acceleration and the size of the affected volume by the pressure wave. The dimensionless number that predicts ultrasonic cavitation is the [[cavitation number|Garcia-Atance number]]. High power ultrasonic horns produce accelerations high enough to create a cavitating region that can be used for [[Homogenization (chemistry)|homogenization]], [[Dispersion (chemistry)|dispersion]], deagglomeration, erosion, cleaning, milling, [[emulsion|emulsification]], extraction, disintegration, and [[sonochemistry]].

~~===Aerodyamic cavitation===~~

Although predominant in liquids, cavitation exists to an extent in gas as it has fluid dynamics at high speeds.<ref>{{Cite web|url=https://www.researchgate.net/figure/Asymmetric-electrode-arrangement-of-an-aerodynamic-plasma-actuator_fig1_253041135|title=Asymmetric electrode arrangement of an aerodynamic plasma actuator. | Download Scientific Diagram}}</ref><ref>{{Cite web|url=https://www.researchgate.net/publication/301889798|title=Simultaneous Investigation of Flexibility and Plasma Actuation Effects on the Aerodynamic Characteristics of an Oscillating Airfoil}}</ref> For example, a [[bullet]] with a flat tip moves faster underwater as it creates cavitation compared to a bullet with a sharp tip. A [[dune]] shape is very useful for managing aerodynamic cavitation. The shape of a dune provides minimal resistance to the wind. With small dunes installed on the surfaces of aircraft and other high speed vehicles, friction against the air decreases by several times. The dune surface pushes the air upwards, underneath and behind areas where the air pressure drops, reducing friction. The dune may increase frontal resistance, but that will be compensated for by a decrease in the total friction area, as also happens with an underwater bullet. As a result, the speed of the aircraft or vehicle will increase significantly.<ref>{{cite web | url=https://contest.techbriefs.com/2019/entries/aerospace-and-defense/9431#:~:text=Contrary%20to%20logic%20and%20general,the%20bullet%20surface%20very%20slightly | title=Aerodynamic Cavitation for Aircraft }}</ref>

==Applications==

===Water transport===

In [[supercavitation]], cavitation is intentionally induced around high-speed submerged objects to reduce [[skin drag]].

===Chemical engineering===

In industry, cavitation is often used to [[Homogenization (chemistry)|homogenize]], or mix and break down, suspended particles in a [[colloidal]] liquid compound such as paint mixtures or milk. Many industrial mixing machines are based upon this design principle. It is usually achieved through impeller design or by forcing the mixture through an annular opening that has a narrow entrance orifice with a much larger exit orifice. In the latter case, the drastic decrease in pressure as the liquid accelerates into a larger volume induces cavitation. This method can be controlled with [[hydraulic]] devices that control inlet orifice size, allowing for dynamic adjustment during the process, or modification for different substances. The surface of this type of mixing valve, against which surface the cavitation bubbles are driven causing their implosion, undergoes tremendous mechanical and thermal localized stress; they are therefore often constructed of extremely strong and hard materials such as [[stainless steel]], [[Stellite]], or even [[polycrystalline diamond]] (PCD).

In industry, cavitation is often used to [[Homogenization (chemistry)|homogenize]], or mix and break down, suspended particles in a [[colloidal]] liquid compound such as paint mixtures or milk. Many industrial mixing machines are based upon this design principle. It is usually achieved through impeller design or by forcing the mixture through an annular opening that has a narrow entrance orifice with a much larger exit orifice. In the latter case, the drastic decrease in pressure as the liquid accelerates into a larger volume induces cavitation. This method can be controlled with [[hydraulic]] devices that control inlet orifice size, allowing for dynamic adjustment during the process, or modification for different substances. The surface of this type of mixing valve, against which surface the cavitation bubbles are driven causing their implosion, undergoes tremendous mechanical and thermal localized stress; they are therefore often constructed of extremely strong and hard materials such as [[stainless steel]], [[Stellite]], or even [[polycrystalline diamond]] (PCD).{{cn|date=September 2025}}

Cavitating [[water purification]] devices have also been designed, in which the extreme conditions of cavitation can break down pollutants and organic molecules. Spectral analysis of light emitted in [[sonochemistry|sonochemical reactions]] reveal chemical and plasma-based mechanisms of energy transfer. The light emitted from cavitation bubbles is termed [[sonoluminescence]].

Cavitating [[water purification]] devices have also been designed, in which the extreme conditions of cavitation can break down pollutants and organic molecules. Spectral analysis of light emitted in [[sonochemistry|sonochemical reactions]] reveal chemical and plasma-based mechanisms of energy transfer. The light emitted from cavitation bubbles is termed [[sonoluminescence]].{{cn|date=September 2025}}

Use of this technology has been tried successfully in alkali refining of vegetable oils.<ref>{{cite web|url=http://www.ctinanotech.com/technology/edible-oil-refining|title=Edible Oil Refining|publisher=Cavitation Technologies, Inc.|access-date=2016-01-04|archive-date=2016-01-29 |archive-url=https://web.archive.org/web/20160129081235/http://www.ctinanotech.com/technology/edible-oil-refining~~|url-status=dead~~}}</ref>

Use of this technology has been tried successfully in alkali refining of vegetable oils.<ref>{{cite web|url=http://www.ctinanotech.com/technology/edible-oil-refining|title=Edible Oil Refining|publisher=Cavitation Technologies, Inc.|access-date=2016-01-04|archive-date=2016-01-29 |archive-url=https://web.archive.org/web/20160129081235/http://www.ctinanotech.com/technology/edible-oil-refining}}</ref>

Hydrophobic chemicals are attracted underwater by cavitation as the pressure difference between the bubbles and the liquid water forces them to join. This effect may assist in [[protein folding]].<ref>{{cite web | url = http://www.sandia.gov/news/resources/releases/2006/snap.html | website = Sandia National Laboratories | date = 2006-08-02 | access-date = 2007-10-17 | title = Sandia researchers solve mystery of attractive surfaces | archive-date = 2007-10-17 | archive-url = https://web.archive.org/web/20071017163015/http://sandia.gov/news/resources/releases/2006/snap.html ~~| url-status = dead~~ }}</ref>

Hydrophobic chemicals are attracted underwater by cavitation as the pressure difference between the bubbles and the liquid water forces them to join. This effect may assist in [[protein folding]].<ref>{{cite web | url = http://www.sandia.gov/news/resources/releases/2006/snap.html | website = Sandia National Laboratories | date = 2006-08-02 | access-date = 2007-10-17 | title = Sandia researchers solve mystery of attractive surfaces | archive-date = 2007-10-17 | archive-url = https://web.archive.org/web/20071017163015/http://sandia.gov/news/resources/releases/2006/snap.html }}</ref>

===Biomedical===

Cavitation plays an important role for the destruction of [[kidney stone]]s in [[extracorporeal shock wave lithotripsy|shock wave lithotripsy]].<ref>{{Cite journal|pmc = 2442573|year = 2003|last1 = Pishchalnikov|first1 = Y. A|title = Cavitation Bubble Cluster Activity in the Breakage of Kidney Stones by Lithotripter Shock Waves|journal = Journal of Endourology|volume = 17|issue = 7|pages = 435–446|last2 = Sapozhnikov|first2 = O. A|last3 = Bailey|first3 = M. R|last4 = Williams Jr|first4 = J. C|last5 = Cleveland|first5 = R. O|last6 = Colonius|first6 = T|last7 = Crum|first7 = L. A|last8 = Evan|first8 = A. P|last9 = McAteer|first9 = J. A|pmid = 14565872|doi = 10.1089/089277903769013568}}</ref> Currently, tests are being conducted as to whether cavitation can be used to transfer large molecules into biological [[cell (biology)|cell]]s ([[sonoporation]]). Nitrogen cavitation is a method used in research to [[lysis|lyse]] cell membranes while leaving organelles intact.

Cavitation plays a key role in non-thermal, non-invasive fractionation of tissue for treatment of a variety of diseases<ref>{{cite web| url = ~~http~~://www.histotripsy.umich.edu/| title = University of Michigan. ''Therapeutic Ultrasound Group, Biomedical Engineering Department, University of Michigan''.}}</ref> and can be used to open the [[Blood–brain barrier|blood-brain barrier]] to increase uptake of neurological drugs in the brain.<ref>{{Cite journal | doi=10.1038/srep33264| pmid=27630037| pmc=5024096| title=Focused Ultrasound-Induced Blood-Brain Barrier Opening: Association with Mechanical Index and Cavitation Index Analyzed by Dynamic Contrast-Enhanced Magnetic-Resonance Imaging| journal=Scientific Reports| volume=6| ~~pages~~=33264| year=2016| last1=Chu| first1=Po-Chun| last2=Chai| first2=Wen-Yen| last3=Tsai| first3=Chih-Hung| last4=Kang| first4=Shih-Tsung| last5=Yeh| first5=Chih-Kuang| last6=Liu| first6=Hao-Li| bibcode=2016NatSR...633264C}}</ref>

Cavitation plays a key role in non-thermal, non-invasive fractionation of tissue for treatment of a variety of diseases<ref>{{cite web| url = https://www.histotripsy.umich.edu/| title = University of Michigan. ''Therapeutic Ultrasound Group, Biomedical Engineering Department, University of Michigan''.}}</ref> and can be used to open the [[Blood–brain barrier|blood-brain barrier]] to increase uptake of neurological drugs in the brain.<ref>{{Cite journal | doi=10.1038/srep33264| pmid=27630037| pmc=5024096| title=Focused Ultrasound-Induced Blood-Brain Barrier Opening: Association with Mechanical Index and Cavitation Index Analyzed by Dynamic Contrast-Enhanced Magnetic-Resonance Imaging| journal=Scientific Reports| volume=6| article-number=33264| year=2016| last1=Chu| first1=Po-Chun| last2=Chai| first2=Wen-Yen| last3=Tsai| first3=Chih-Hung| last4=Kang| first4=Shih-Tsung| last5=Yeh| first5=Chih-Kuang| last6=Liu| first6=Hao-Li| bibcode=2016NatSR...633264C}}</ref>

Cavitation also plays a role in [[HIFU]], a thermal non-invasive treatment methodology for [[cancer]].<ref>{{Cite journal|last1=Rabkin|first1=Brian A.|last2=Zderic|first2=Vesna|last3=Vaezy|first3=Shahram|date=2005-07-01 |title=Hyperecho in ultrasound images of HIFU therapy: Involvement of cavitation|journal=Ultrasound in Medicine and Biology|volume=31|issue=7|pages=947–956|doi=10.1016/j.ultrasmedbio.2005.03.015|issn=0301-5629|pmid=15972200}}</ref>

In wounds caused by high velocity impacts (like for example bullet wounds) there are also effects due to cavitation. The exact wounding mechanisms are not completely understood yet as there is temporary cavitation, and permanent cavitation together with crushing, tearing and stretching. Also the high variance in density within the body makes it hard to determine its effects.<ref>{{Cite journal|last1=Stefanopoulos |first1=Panagiotis K.|last2=Mikros |first2=George|last3=Pinialidis|first3=Dionisios E.|last4=Oikonomakis |first4=Ioannis N.|last5=Tsiatis|first5=Nikolaos E.|last6=Janzon|first6=Bo|date=2009-09-01|title=Wound ballistics of military rifle bullets: An update on controversial issues and associated misconceptions |journal=The Journal of Trauma and Acute Care Surgery|volume=87|issue=3|pages=690–698|pmid=30939579 |s2cid=92996795|doi=10.1097/TA.0000000000002290}}</ref>

In wounds caused by high velocity impacts (like for example bullet wounds) there are also effects due to cavitation. The exact wounding mechanisms are not completely understood yet as there is temporary cavitation, and permanent cavitation {{clarify|what is permanent cavitation?|date=September 2025}} together with crushing, tearing and stretching. Also the high variance in density within the body makes it hard to determine its effects.<ref>{{Cite journal|last1=Stefanopoulos |first1=Panagiotis K.|last2=Mikros |first2=George|last3=Pinialidis|first3=Dionisios E.|last4=Oikonomakis |first4=Ioannis N.|last5=Tsiatis|first5=Nikolaos E.|last6=Janzon|first6=Bo|date=2009-09-01|title=Wound ballistics of military rifle bullets: An update on controversial issues and associated misconceptions |journal=The Journal of Trauma and Acute Care Surgery|volume=87|issue=3|pages=690–698|pmid=30939579 |s2cid=92996795|doi=10.1097/TA.0000000000002290}}</ref>

Ultrasound sometimes is used to increase bone formation, for instance in post-surgical applications.<ref>{{cite web|url=http://www.physiomontreal.com/Ultrasound.pdf |archive-url=https://web.archive.org/web/20030309225204/http://www.physiomontreal.com/Ultrasound.pdf |archive-date=2003-03-09 |url-status=live|title=Physio Montreal Article "Ultrasound"}}</ref>

Ultrasound sometimes is used to increase bone formation, for instance in post-surgical applications.{{clarify|what is the relevance to cavitation? Ultrasound does not imply cavitation.|date=September 2025}}<ref>{{cite web|url=http://www.physiomontreal.com/Ultrasound.pdf |archive-url=https://web.archive.org/web/20030309225204/http://www.physiomontreal.com/Ultrasound.pdf |archive-date=2003-03-09 |url-status=live|title=Physio Montreal Article "Ultrasound"}}</ref>

It has been suggested that the sound of [[cracking joints|"cracking" knuckles]] derives from the collapse of cavitation in the [[synovial fluid]] within the joint.<ref>{{cite journal|last=Unsworth|first=A|author2=Dowson, D|author3=Wright, V|title='Cracking joints'. A bioengineering study of cavitation in the metacarpophalangeal joint|journal=Annals of the Rheumatic Diseases|date=July 1971|volume=30|issue=4|pages=348–58|pmid=5557778|doi=10.1136/ard.30.4.348|pmc=1005793}}</ref>

Cavitation can also form [[Ozone micro-nanobubbles]] which shows promise in dental applications.<ref>{{Cite journal |last1=Hauser-Gerspach |first1=Irmgard |last2=Vadaszan |first2=Jasminka |last3=Deronjic |first3=Irma |last4=Gass |first4=Catiana |last5=Meyer |first5=Jürg |last6=Dard |first6=Michel |last7=Waltimo |first7=Tuomas |last8=Stübinger |first8=Stefan |last9=Mauth |first9=Corinna |date=2011-08-13 |title=Influence of gaseous ozone in peri-implantitis: bactericidal efficacy and cellular response. An in vitro study using titanium and zirconia ~~|url=http://dx.doi.org/10.1007/s00784-011-0603-2~~ |journal=Clinical Oral Investigations |volume=16 |issue=4 |pages=1049–1059 |doi=10.1007/s00784-011-0603-2 |pmid=21842144 |s2cid=10747305 |issn=1432-6981~~|url-access=subscription~~ }}</ref>

Cavitation can also form [[Ozone micro-nanobubbles]] which shows promise in dental applications.<ref>{{Cite journal |last1=Hauser-Gerspach |first1=Irmgard |last2=Vadaszan |first2=Jasminka |last3=Deronjic |first3=Irma |last4=Gass |first4=Catiana |last5=Meyer |first5=Jürg |last6=Dard |first6=Michel |last7=Waltimo |first7=Tuomas |last8=Stübinger |first8=Stefan |last9=Mauth |first9=Corinna |date=2011-08-13 |title=Influence of gaseous ozone in peri-implantitis: bactericidal efficacy and cellular response. An in vitro study using titanium and zirconia |journal=Clinical Oral Investigations |volume=16 |issue=4 |pages=1049–1059 |doi=10.1007/s00784-011-0603-2 |pmid=21842144 |s2cid=10747305 |issn=1432-6981}}</ref>

===Cleaning===

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==== Biodiesel ====

Cavitation has been applied to Biodiesel production since 2011 and is considered a proven and standard technology in this application. The implementation of hydrodynamic cavitation in the transesterification process allows for a significant reduction in catalyst use, quality improvement and production capacity increase.<ref>{{cite web |url=~~http~~://www.biodieselmagazine.com/articles/8457/hero-bx-adopts-cavitation-tech-to-reduce-catalyst-use-monos |access-date=2022-05-19 |author=Arisdyne Systems |date=April 27, 2012 |title=Hero BX adopts cavitation tech to reduce catalyst use, monos |work=Biodiesel Magazine}}</ref><ref>{{Cite web|url=https://patents.justia.com/patent/9000244|title=US Patent for Process for production of biodiesel Patent (Patent # 9,000,244 issued April 7, 2015) - Justia Patents Search|website=patents.justia.com}}</ref><ref>{{Cite web|url=https://patents.justia.com/patent/20100175309|title=US Patent Application for PROCESS FOR IMPROVED BIODIESEL FUEL Patent Application (Application #20100175309 issued July 15, 2010) - Justia Patents Search|website=patents.justia.com}}</ref>

Cavitation has been applied to Biodiesel production since 2011 and is considered a proven and standard technology in this application. The implementation of hydrodynamic cavitation in the transesterification process allows for a significant reduction in catalyst use, quality improvement and production capacity increase.<ref>{{cite web |url=https://www.biodieselmagazine.com/articles/8457/hero-bx-adopts-cavitation-tech-to-reduce-catalyst-use-monos |access-date=2022-05-19 |author=Arisdyne Systems |date=April 27, 2012 |title=Hero BX adopts cavitation tech to reduce catalyst use, monos |work=Biodiesel Magazine}}</ref><ref>{{Cite web|url=https://patents.justia.com/patent/9000244|title=US Patent for Process for production of biodiesel Patent (Patent # 9,000,244 issued April 7, 2015) - Justia Patents Search|website=patents.justia.com}}</ref><ref>{{Cite web|url=https://patents.justia.com/patent/20100175309|title=US Patent Application for PROCESS FOR IMPROVED BIODIESEL FUEL Patent Application (Application #20100175309 issued July 15, 2010) - Justia Patents Search|website=patents.justia.com}}</ref>

==Cavitation damage{{anchor|Cavitation erosion}}==

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[[Suction]] cavitation occurs when the pump suction is under a low-pressure/high-vacuum condition where the liquid turns into a vapor at the eye of the pump impeller. This vapor is carried over to the discharge side of the pump, where it no longer sees vacuum and is compressed back into a liquid by the discharge pressure. This imploding action occurs violently and attacks the face of the impeller. An impeller that has been operating under a suction cavitation condition can have large chunks of material removed from its face or very small bits of material removed, causing the impeller to look spongelike. Both cases will cause premature failure of the pump, often due to bearing failure. Suction cavitation is often identified by a sound like gravel or marbles in the pump casing.

Common causes of suction cavitation can include clogged filters, pipe blockage on the suction side, poor piping design, pump running too far right on the pump curve, or conditions not meeting [[Net positive suction head|NPSH]] (net positive suction head) requirements.<ref>{{Cite news|url=https://info.triangle-pump.com/blog/pump-cavitation|title=Common Causes of Cavitation in Pumps|last=Kelton|first=Sam|date=May 16, 2017|publisher=Triangle Pump Components|access-date=2018-07-16|archive-date=2018-07-16 |archive-url=https://web.archive.org/web/20180716224100/https://info.triangle-pump.com/blog/pump-cavitation~~|url-status=dead~~}}</ref>

Common causes of suction cavitation can include clogged filters, pipe blockage on the suction side, poor piping design, pump running too far right on the pump curve, or conditions not meeting [[Net positive suction head|NPSH]] (net positive suction head) requirements.<ref>{{Cite news|url=https://info.triangle-pump.com/blog/pump-cavitation|title=Common Causes of Cavitation in Pumps|last=Kelton|first=Sam|date=May 16, 2017|publisher=Triangle Pump Components|access-date=2018-07-16|archive-date=2018-07-16 |archive-url=https://web.archive.org/web/20180716224100/https://info.triangle-pump.com/blog/pump-cavitation}}</ref>

In automotive applications, a clogged filter in a hydraulic system (power steering, power brakes) can cause suction cavitation making a noise that rises and falls in synch with engine RPM. It is fairly often a high pitched whine, like set of nylon gears not quite meshing correctly.

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Since all pumps require well-developed inlet flow to meet their potential, a pump may not perform or be as reliable as expected due to a faulty suction piping layout such as a close-coupled elbow on the inlet flange. When poorly developed flow enters the pump impeller, it strikes the vanes and is unable to follow the impeller passage. The liquid then separates from the vanes causing mechanical problems due to cavitation, vibration and performance problems due to turbulence and poor filling of the impeller. This results in premature seal, bearing and impeller failure, high maintenance costs, high power consumption, and less-than-specified head and/or flow.

To have a well-developed flow pattern, pump manufacturer's manuals recommend about (10 diameters?) of straight pipe run upstream of the pump inlet flange. Unfortunately, piping designers and plant personnel must contend with space and equipment layout constraints and usually cannot comply with this recommendation. Instead, it is common to use an elbow close-coupled to the pump suction which creates a poorly developed flow pattern at the pump suction.<ref>{{cite ~~web~~| last=Golomb| first=Richard| title=A new tailpipe design for GE frame-type gas turbines to substantially lower pressure losses |url=http://cat.inist.fr/?aModele=afficheN&cpsidt=1454644|publisher=American Society of Mechanical Engineers| access-date=2 August 2012}}</ref>

To have a well-developed flow pattern, pump manufacturer's manuals recommend about (10 diameters?) of straight pipe run upstream of the pump inlet flange. Unfortunately, piping designers and plant personnel must contend with space and equipment layout constraints and usually cannot comply with this recommendation. Instead, it is common to use an elbow close-coupled to the pump suction which creates a poorly developed flow pattern at the pump suction.<ref>{{cite journal| last=Golomb| first=Richard| title=A new tailpipe design for GE frame-type gas turbines to substantially lower pressure losses | journal=Journal of Clinical Neuroscience| volume=7| issue=5|url=http://cat.inist.fr/?aModele=afficheN&cpsidt=1454644|publisher=American Society of Mechanical Engineers| access-date=2 August 2012}}</ref>

With a double-suction pump tied to a close-coupled elbow, flow distribution to the impeller is poor and causes reliability and performance shortfalls. The elbow divides the flow unevenly with more channeled to the outside of the elbow. Consequently, one side of the double-suction impeller receives more flow at a higher flow velocity and pressure while the starved side receives a highly turbulent and potentially damaging flow. This degrades overall pump performance (delivered head, flow and power consumption) and causes axial imbalance which shortens seal, bearing and impeller life.<ref>[[Pulp & Paper]] (1992), Daishowa Reduces Pump Maintenance by Installing Fluid Rotating Vanes</ref>

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===Spore dispersal in plants===

Cavitation plays a role in the spore dispersal mechanisms of certain plants. In [[fern]]s, for example, the fern sporangium acts as a catapult that launches spores into the air. The charging phase of the catapult is driven by water evaporation from the [[annulus (botany)|annulus]] cells, which triggers a pressure decrease. When the compressive pressure reaches approximately 9{{nbsp}}[[Pascal (unit)|MPa]], cavitation occurs. This rapid event triggers spore dispersal due to the [[elastic energy]] released by the annulus structure. The initial spore acceleration is extremely large – up to 10{{sup|5}} times the [[gravitational acceleration]].<ref name="NoblinRojas2012">{{cite journal |last1=Noblin|first1=X.|last2=Rojas|first2=N. O. |last3=Westbrook|first3=J.|last4=Llorens|first4=C.|last5=Argentina|first5=M.|last6=Dumais|first6=J. |title=The Fern Sporangium: A Unique Catapult|journal=Science|volume=335 |issue=6074|year=2012|~~pages~~=1322 |issn=0036-8075|doi=10.1126/science.1215985|pmid=22422975|bibcode=2012Sci...335.1322N|s2cid=20037857 |url=https://hal.archives-ouvertes.fr/hal-00826001/file/1215985_maintext-resumitted2-for-HAL.pdf |archive-url=https://web.archive.org/web/20190504014851/https://hal.archives-ouvertes.fr/hal-00826001/file/1215985_maintext-resumitted2-for-HAL.pdf |archive-date=2019-05-04 |url-status=live}}</ref>

Cavitation plays a role in the spore dispersal mechanisms of certain plants. In [[fern]]s, for example, the fern sporangium acts as a catapult that launches spores into the air. The charging phase of the catapult is driven by water evaporation from the [[annulus (botany)|annulus]] cells, which triggers a pressure decrease. When the compressive pressure reaches approximately 9{{nbsp}}[[Pascal (unit)|MPa]], cavitation occurs. This rapid event triggers spore dispersal due to the [[elastic energy]] released by the annulus structure. The initial spore acceleration is extremely large – up to 10{{sup|5}} times the [[gravitational acceleration]].<ref name="NoblinRojas2012">{{cite journal |last1=Noblin|first1=X.|last2=Rojas|first2=N. O. |last3=Westbrook|first3=J.|last4=Llorens|first4=C.|last5=Argentina|first5=M.|last6=Dumais|first6=J. |title=The Fern Sporangium: A Unique Catapult|journal=Science|volume=335 |issue=6074|year=2012|page=1322 |issn=0036-8075|doi=10.1126/science.1215985|pmid=22422975|bibcode=2012Sci...335.1322N|s2cid=20037857 |url=https://hal.archives-ouvertes.fr/hal-00826001/file/1215985_maintext-resumitted2-for-HAL.pdf |archive-url=https://web.archive.org/web/20190504014851/https://hal.archives-ouvertes.fr/hal-00826001/file/1215985_maintext-resumitted2-for-HAL.pdf |archive-date=2019-05-04 |url-status=live}}</ref>

===Marine life===

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Cavitation may limit the maximum swimming speed of powerful swimming animals like [[dolphins]] and [[tuna]].<ref>{{cite magazine | last = Brahic | first = Catherine | title = Dolphins swim so fast it hurts | magazine = New Scientist | date = 2008-03-28 | url = https://www.newscientist.com/channel/life/dn13553-dolphins-swim-so-fast-it-hurts.html | access-date = 2008-03-31}}</ref> Dolphins may have to restrict their speed because collapsing cavitation bubbles on their tail are painful. Tuna have bony fins without nerve endings and do not feel pain from cavitation. They are slowed down when cavitation bubbles create a vapor film around their fins. Lesions have been found on tuna that are consistent with cavitation damage.<ref name="IosilevskiiWeihs2008">{{cite journal|last1=Iosilevskii|first1=G|last2=Weihs|first2=D|title=Speed limits on swimming of fishes and cetaceans|journal=Journal of the Royal Society Interface|volume=5|issue=20|year=2008|pages=329–338|issn=1742-5689|doi=10.1098/rsif.2007.1073|pmid=17580289|pmc=2607394}}</ref>

Some sea animals have found ways to use cavitation to their advantage when hunting prey. The [[pistol shrimp]] snaps a specialized claw to create cavitation, which can kill small fish. The [[mantis shrimp]] (of the ''smasher'' variety) uses cavitation as well in order to stun, smash open, or kill the shellfish that it feasts upon.<ref>{{cite web|last=Patek|first=Sheila|title=Sheila Patek clocks the fastest animals|url=~~http~~://www.ted.com/talks/~~sheila_patek_clocks_the_fastest_animals.html~~|publisher=TED|access-date=18 February 2011}}</ref>

Some sea animals have found ways to use cavitation to their advantage when hunting prey. The [[pistol shrimp]] snaps a specialized claw to create cavitation, which can kill small fish. The [[mantis shrimp]] (of the ''smasher'' variety) uses cavitation as well in order to stun, smash open, or kill the shellfish that it feasts upon.<ref>{{cite web|last=Patek|first=Sheila|title=Sheila Patek clocks the fastest animals|date=April 5, 2007 |url=https://www.ted.com/talks/sheila_patek_the_shrimp_with_a_kick|publisher=TED|access-date=18 February 2011}}</ref>

[[Thresher sharks]] use 'tail slaps' to debilitate their small fish prey and cavitation bubbles have been seen rising from the apex of the tail arc.<ref name="TsiklirasOliver2013">{{cite journal|last1=Tsikliras|first1=Athanassios C.|last2=Oliver|first2=Simon P.|last3=Turner|first3=John R.|last4=Gann|first4=Klemens|last5=Silvosa|first5=Medel|last6=D'Urban Jackson|first6=Tim|title=Thresher Sharks Use Tail-Slaps as a Hunting Strategy|journal=PLOS ONE|volume=8|issue=7|year=2013|~~pages~~=e67380|issn=1932-6203|doi=10.1371/journal.pone.0067380|pmid=23874415|pmc=3707734|bibcode = 2013PLoSO...867380O |doi-access=free}}</ref><ref>Archived at [https://ghostarchive.org/varchive/youtube/20211205/lHoCCPsRuhg Ghostarchive]{{cbignore}} and the [https://web.archive.org/web/20130825141415/http://www.youtube.com/watch?v=lHoCCPsRuhg&gl=US&hl=en Wayback Machine]{{cbignore}}: {{cite web| url = https://www.youtube.com/watch?v=lHoCCPsRuhg| title = THRESHER SHARKS KILL PREY WITH TAIL | website=[[YouTube]]| date = July 12, 2013 }}{{cbignore}}</ref>

[[Thresher sharks]] use 'tail slaps' to debilitate their small fish prey and cavitation bubbles have been seen rising from the apex of the tail arc.<ref name="TsiklirasOliver2013">{{cite journal|last1=Tsikliras|first1=Athanassios C.|last2=Oliver|first2=Simon P.|last3=Turner|first3=John R.|last4=Gann|first4=Klemens|last5=Silvosa|first5=Medel|last6=D'Urban Jackson|first6=Tim|title=Thresher Sharks Use Tail-Slaps as a Hunting Strategy|journal=PLOS ONE|volume=8|issue=7|year=2013|article-number=e67380|issn=1932-6203|doi=10.1371/journal.pone.0067380|pmid=23874415|pmc=3707734|bibcode = 2013PLoSO...867380O |doi-access=free}}</ref><ref>Archived at [https://ghostarchive.org/varchive/youtube/20211205/lHoCCPsRuhg Ghostarchive]{{cbignore}} and the [https://web.archive.org/web/20130825141415/http://www.youtube.com/watch?v=lHoCCPsRuhg&gl=US&hl=en Wayback Machine]{{cbignore}}: {{cite web| url = https://www.youtube.com/watch?v=lHoCCPsRuhg| title = THRESHER SHARKS KILL PREY WITH TAIL | website=[[YouTube]]| date = July 12, 2013 }}{{cbignore}}</ref>

===Coastal erosion===

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== History ==

As early as 1754, the Swiss mathematician [[Leonhard Euler]] (1707–1783) speculated about the possibility of cavitation.<ref>{{cite journal |last1=Euler |title=Théorie plus complete des machines qui sont mises en mouvement par la réaction de l'eau |journal=Mémoires de l'Académie Royale des Sciences et Belles-Lettres (Berlin) |date=1754 |volume=10 |pages=227–295 |language=fr |url=https://babel.hathitrust.org/cgi/pt?id=mdp.39015038659283;view=1up;seq=271 |trans-title=A more complete theory of machines that are set in motion by reaction against water}} See §LXXXI, pp. 266–267. From p. 266: ''"Il pourroit donc arriver que la pression en M devint même négative, & alors l'eau abandonneroit les parois du tuyau, & y laisseroit un vuide, si elle n'étoit pas comprimée par le poids de l'atmosphère."'' (It could therefore happen that the pressure in M might even become negative, and then the water would let go of the walls of the pipe, and would leave a void there, if it were not compressed by the weight of the atmosphere.)</ref> In 1859, the English mathematician [[W. H. Besant|William Henry Besant]] (1828–1917) published a solution to the problem of the dynamics of the collapse of a spherical cavity in a fluid, which had been presented by the Anglo-Irish mathematician [[Sir George Stokes, 1st Baronet|George Stokes]] (1819–1903) as one of the Cambridge [University] Senate-house problems and riders for the year 1847.<ref>{{cite book |last1=Besant |first1=W. H. |title=A Treatise on Hydrostatics and Hydrodynamics |date=1859 |publisher=Deighton, Bell, and Co. |location=Cambridge, England |pages=[https://archive.org/details/atreatiseonhydr01besagoog/page/n183 170]–171 |url=https://archive.org/details/atreatiseonhydr01besagoog}}</ref><ref>{{cite book |last1=(University of Cambridge) |title=The Examinations for the Degree of Bachelor of Arts, Cambridge, January 1847. |date=1847 |publisher=George Bell |location=London, England |page=13, problem 23 |chapter-url=https://books.google.com/books?id=kpxeAAAAcAAJ&pg=PA13 |chapter=The Senate-house Examination for Degrees in Honors, 1847.}}</ref>{{sfnp|Cravotto|Cintas|2012|p=26}} In 1894, Irish fluid dynamicist [[Osborne Reynolds]] (1842–1912) studied the formation and collapse of vapor bubbles in boiling liquids and in constricted tubes.<ref>See:

As early as 1754, the Swiss mathematician [[Leonhard Euler]] (1707–1783) speculated about the possibility of cavitation.<ref>{{cite journal |last1=Euler |title=Théorie plus complete des machines qui sont mises en mouvement par la réaction de l'eau |journal=Mémoires de l'Académie Royale des Sciences et Belles-Lettres (Berlin) |date=1754 |volume=10 |pages=227–295 |language=fr |url=https://babel.hathitrust.org/cgi/pt?id=mdp.39015038659283;view=1up;seq=271 |trans-title=A more complete theory of machines that are set in motion by reaction against water}} See §LXXXI, pp. 266–267. From p. 266: ''"Il pourroit donc arriver que la pression en M devint même négative, & alors l'eau abandonneroit les parois du tuyau, & y laisseroit un vuide, si elle n'étoit pas comprimée par le poids de l'atmosphère."'' (It could therefore happen that the pressure in M might even become negative, and then the water would let go of the walls of the pipe, and would leave a void there, if it were not compressed by the weight of the atmosphere.)</ref> In 1859, the English mathematician [[W. H. Besant|William Henry Besant]] (1828–1917) published a solution to the problem of the dynamics of the collapse of a spherical cavity in a fluid, which had been presented by the Anglo-Irish mathematician [[Sir George Stokes, 1st Baronet|George Stokes]] (1819–1903) as one of the Cambridge University Senate-house problems and riders for the year 1847.<ref>{{cite book |last1=Besant |first1=W. H. |title=A Treatise on Hydrostatics and Hydrodynamics |date=1859 |publisher=Deighton, Bell, and Co. |location=Cambridge, England |pages=[https://archive.org/details/atreatiseonhydr01besagoog/page/n183 170]–171 |url=https://archive.org/details/atreatiseonhydr01besagoog}}</ref><ref>{{cite book |last1=(University of Cambridge) |title=The Examinations for the Degree of Bachelor of Arts, Cambridge, January 1847. |date=1847 |publisher=George Bell |location=London, England |page=13, problem 23 |chapter-url=https://books.google.com/books?id=kpxeAAAAcAAJ&pg=PA13 |chapter=The Senate-house Examination for Degrees in Honors, 1847.}}</ref>{{sfnp|Cravotto|Cintas|2012|p=26}} In 1894, Irish fluid dynamicist [[Osborne Reynolds]] (1842–1912) studied the formation and collapse of vapor bubbles in boiling liquids and in constricted tubes.<ref>See:

* {{cite journal |last1=Reynolds |first1=Osborne |title=Experiments showing the boiling of water in an open tube at ordinary temperatures |journal=Report of the Sixty-fourth Meeting of the British Association for the Advancement of Science Held at Oxford in August 1894 |date=1894 |volume=64 |page=564 |url=https://www.biodiversitylibrary.org/item/95243#page/688/mode/1up}}

* {{cite book |last1=Reynolds |first1=Osborne |title=Papers on Mechanical and Physical Subjects |date=1901 |publisher=Cambridge University Press |location=Cambridge, England |volume=2 |pages=578–587 |chapter-url=https://archive.org/details/papersonmechanic02reynrich/page/578 |chapter=Experiments showing the boiling of water in an open tube at ordinary temperatures}}</ref>

The term ''cavitation'' first appeared in 1895 in a paper by [[John Isaac Thornycroft]] (1843–1928) and Sydney Walker Barnaby (1855–1925)—son of Sir [[Nathaniel Barnaby]] (1829 – 1915), who had been Chief Constructor of the Royal Navy—to whom it had been suggested by the British engineer Robert Edmund Froude (1846–1924), third son of the English hydrodynamicist [[William Froude]] (1810–1879).<ref>{{cite journal |last1=Thornycroft |first1=John Isaac |last2=Barnaby |first2=Sydney Walker |title=Torpedo-boat destroyers |journal=Minutes of the Proceedings of the Institution of Civil Engineers |date=1895 |volume=122 |issue=1895 |pages=51–69 |doi=10.1680/imotp.1895.19693 |url=https://babel.hathitrust.org/cgi/pt?id=hvd.hxgrq5;view=1up;seq=65}} From p. 67: " 'Cavitation,' as Mr. Froude has suggested to the Authors that the phenomenon should be called, … "</ref><ref>{{cite book |last1=Cravotto |first1=Giancarlo |last2=Cintas |first2=Pedro |editor1-last=Chen |editor1-first=Dong |editor2-last=Sharma |editor2-first=Sanjay K. |editor3-last=Mudhoo |editor3-first=Ackmez |title=Handbook on Applications of Ultrasound: Sonochemistry for Sustainability |date=2012 |publisher=CRC Press |location=Boca Raton, Florida, USA |page=27 |chapter-url=https://books.google.com/books?id=dSDOBQAAQBAJ&pg=PA27 |chapter=Chapter 2. Introduction to sonochemistry: A historical and conceptual overview|isbn=~~9781439842072~~ }}</ref> Early experimental studies of cavitation were conducted in 1894–5 by Thornycroft and Barnaby and by the Anglo-Irish engineer [[Charles Algernon Parsons]] (1854–1931), who constructed a stroboscopic apparatus to study the phenomenon.<ref>{{cite journal |last1=Barnaby |first1=Sydney W. |title=On the formation of cavities in water by screw propellers at high speeds |journal=Transactions of the Royal Institution of Naval Architects |date=1897 |volume=39 |pages=139–144 |url=https://books.google.com/books?id=QtQ6AAAAMAAJ&pg=PA139}}</ref><ref>{{cite journal |last1=Parsons |first1=Charles |title=The application of the compound steam turbine to the purpose of marine propulsion |journal=Transactions of the Royal Institution of Naval Architects |date=1897 |volume=38 |pages=232–242 |url=https://books.google.com/books?id=Di85AQAAMAAJ&pg=PA232}} The stroboscope is described on p. 234: "The screw [i.e., propeller] was illuminated by light from an arc lamp reflected from a revolving mirror attached to the screw shaft, which fell on it at one point only of the revolution, and by this means the shape, form, and growth of the cavities could be clearly seen and traced as if stationary."</ref><ref>See:

The term ''cavitation'' first appeared in 1895 in a paper by [[John Isaac Thornycroft]] (1843–1928) and Sydney Walker Barnaby (1855–1925)—son of Sir [[Nathaniel Barnaby]] (1829 – 1915), who had been Chief Constructor of the Royal Navy—to whom it had been suggested by the British engineer Robert Edmund Froude (1846–1924), third son of the English hydrodynamicist [[William Froude]] (1810–1879).<ref>{{cite journal |last1=Thornycroft |first1=John Isaac |last2=Barnaby |first2=Sydney Walker |title=Torpedo-boat destroyers |journal=Minutes of the Proceedings of the Institution of Civil Engineers |date=1895 |volume=122 |issue=1895 |pages=51–69 |doi=10.1680/imotp.1895.19693 |url=https://babel.hathitrust.org/cgi/pt?id=hvd.hxgrq5;view=1up;seq=65}} From p. 67: " 'Cavitation,' as Mr. Froude has suggested to the Authors that the phenomenon should be called, … "</ref><ref>{{cite book |last1=Cravotto |first1=Giancarlo |last2=Cintas |first2=Pedro |editor1-last=Chen |editor1-first=Dong |editor2-last=Sharma |editor2-first=Sanjay K. |editor3-last=Mudhoo |editor3-first=Ackmez |title=Handbook on Applications of Ultrasound: Sonochemistry for Sustainability |date=2012 |publisher=CRC Press |location=Boca Raton, Florida, USA |page=27 |chapter-url=https://books.google.com/books?id=dSDOBQAAQBAJ&pg=PA27 |chapter=Chapter 2. Introduction to sonochemistry: A historical and conceptual overview|isbn=978-1-4398-4207-2 }}</ref> Early experimental studies of cavitation were conducted in 1894–5 by Thornycroft and Barnaby and by the Anglo-Irish engineer [[Charles Algernon Parsons]] (1854–1931), who constructed a stroboscopic apparatus to study the phenomenon.<ref>{{cite journal |last1=Barnaby |first1=Sydney W. |title=On the formation of cavities in water by screw propellers at high speeds |journal=Transactions of the Royal Institution of Naval Architects |date=1897 |volume=39 |pages=139–144 |url=https://books.google.com/books?id=QtQ6AAAAMAAJ&pg=PA139}}</ref><ref>{{cite journal |last1=Parsons |first1=Charles |title=The application of the compound steam turbine to the purpose of marine propulsion |journal=Transactions of the Royal Institution of Naval Architects |date=1897 |volume=38 |pages=232–242 |url=https://books.google.com/books?id=Di85AQAAMAAJ&pg=PA232}} The stroboscope is described on p. 234: "The screw [i.e., propeller] was illuminated by light from an arc lamp reflected from a revolving mirror attached to the screw shaft, which fell on it at one point only of the revolution, and by this means the shape, form, and growth of the cavities could be clearly seen and traced as if stationary."</ref><ref>See:

* Parsons, Charles A. (1934) "Motive power — high-speed navigation steam turbines [address to the Royal Institution of Great Britain, delivered on 26 January 1900]". Parsons, G.L. (ed.). ''Scientific Papers and Addresses of the Hon. Sir Charles A. Parsons''. Cambridge England: Cambridge University Press. pp. 26–35.

* {{cite journal |last1=Parsons |first1=Charles A. |title=Experimental apparatus shewing cavitation in screw propellers |journal=Transactions - North East Coast Institution of Engineers and Shipbuilders |date=1913 |volume=29 |pages=300–302 |url=https://babel.hathitrust.org/cgi/pt?id=mdp.39015039810455&view=1up&seq=434}}

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* {{cite journal |last1=Parsons |first1=Charles A. |last2=Cook |first2=Stanley S. |title=Investigations into the causes of corrosion or erosion of propellers |journal=Transactions of the Institution of Naval Architects |date=1919 |volume=61 |pages=223–247 |url=https://babel.hathitrust.org/cgi/pt?id=mdp.39015022701232;view=1up;seq=295}}

* {{cite journal |last1=Parsons |first1=Charles A. |last2=Cook |first2=Stanley S. |title=Investigations into the causes of corrosion or erosion of propellers |journal=Engineering |date=18 April 1919 |volume=107 |pages=515–519 |url=https://babel.hathitrust.org/cgi/pt?id=mdp.39015084594426;view=1up;seq=623}}

* {{cite journal |last1=Gibb |first1=Claude |title=Stanley Smith Cook. 1875-1952 |journal=Obituary Notices of Fellows of the Royal Society |date=November 1952 |volume=8 |issue=21 |pages=118–127|doi=10.1098/rsbm.1952.0008 |s2cid=119838312 }}; see pp. 123–124.</ref> Experimental evidence of cavitation causing such high pressures was initially collected in 1952 by Mark Harrison (a fluid dynamicist and acoustician at the U.S. Navy's David Taylor Model Basin at Carderock, Maryland, USA) who used acoustic methods and in 1956 by Wernfried Güth (a physicist and acoustician of Göttigen University, Germany) who used optical [[Schlieren photography]].<ref>{{cite journal |last1=Harrison |first1=Mark |title=An experimental study of single bubble cavitation noise |journal=Journal of the Acoustical Society of America |date=1952 |volume=24 |issue=6 |pages=776–782|doi=10.1121/1.1906978 |bibcode=1952ASAJ...24..776H }}</ref><ref>{{cite journal |last1=Güth |first1=Wernfried |title=Entstehung der Stoßwellen bei der Kavitation |journal=Acustica |date=1956 |volume=6 |pages=526–531 |trans-title=Origin of shock waves during cavitation |language=de}}</ref><ref>{{cite book |last1=Krehl |first1=Peter O. K. |title=History of Shock Waves, Explosions and Impact: A Chronological and Biographical Reference |date=2009 |publisher=Springer Verlag |location=Berlin and Heidelberg, Germany |page=461 |url=https://books.google.com/books?id=PmuqCHDC3pwC&pg=PA461|isbn=~~9783540304210~~ }}</ref>

* {{cite journal |last1=Gibb |first1=Claude |title=Stanley Smith Cook. 1875-1952 |journal=Obituary Notices of Fellows of the Royal Society |date=November 1952 |volume=8 |issue=21 |pages=118–127|doi=10.1098/rsbm.1952.0008 |doi-access=free|s2cid=119838312 }}; see pp. 123–124.</ref> Experimental evidence of cavitation causing such high pressures was initially collected in 1952 by Mark Harrison (a fluid dynamicist and acoustician at the U.S. Navy's David Taylor Model Basin at Carderock, Maryland, USA) who used acoustic methods and in 1956 by Wernfried Güth (a physicist and acoustician of Göttigen University, Germany) who used optical [[Schlieren photography]].<ref>{{cite journal |last1=Harrison |first1=Mark |title=An experimental study of single bubble cavitation noise |journal=Journal of the Acoustical Society of America |date=1952 |volume=24 |issue=6 |pages=776–782|doi=10.1121/1.1906978 |bibcode=1952ASAJ...24..776H }}</ref><ref>{{cite journal |last1=Güth |first1=Wernfried |title=Entstehung der Stoßwellen bei der Kavitation |journal=Acustica |date=1956 |volume=6 |pages=526–531 |trans-title=Origin of shock waves during cavitation |language=de}}</ref><ref>{{cite book |last1=Krehl |first1=Peter O. K. |title=History of Shock Waves, Explosions and Impact: A Chronological and Biographical Reference |date=2009 |publisher=Springer Verlag |location=Berlin and Heidelberg, Germany |page=461 |url=https://books.google.com/books?id=PmuqCHDC3pwC&pg=PA461|isbn=978-3-540-30421-0 }}</ref>

[[File:Cavitation bubble implosion.png|right|frame|The implosion of a cavitation bubble causes a high-speed jet of fluid to impact a fixed surface]]

In 1944, Soviet scientists Mark Iosifovich Kornfeld (1908–1993) and L. Suvorov of the Leningrad Physico-Technical Institute (now: the Ioffe Physical-Technical Institute of the Russian Academy of Sciences, St. Petersburg, Russia) proposed that during cavitation, bubbles in the vicinity of a solid surface do not collapse symmetrically; instead, a dimple forms on the bubble at a point opposite the solid surface and this dimple evolves into a jet of liquid. This jet of liquid damages the solid surface.<ref>{{cite journal |last1=Kornfeld |first1=M. |last2=Suvorov |first2=L. |title=On the destructive action of cavitation |journal=Journal of Applied Physics |date=1944 |volume=15 |issue=6 |pages=495–506|doi=10.1063/1.1707461 |bibcode=1944JAP....15..495K }}</ref> This hypothesis was supported in 1951 by theoretical studies by Maurice Rattray Jr., a doctoral student at the [[California Institute of Technology]].<ref>Rattray, Maurice, Jr. (1951) [https://thesis.library.caltech.edu/1493/1/Rattray_m_1951.pdf ''Perturbation effects in cavitation bubble dynamics.''] Ph.D. thesis, California Institute of Technology (Pasadena, California, USA).</ref> Kornfeld and Suvorov's hypothesis was confirmed experimentally in 1961 by Charles F. Naudé and Albert T. Ellis, fluid dynamicists at the California Institute of Technology.<ref>{{cite journal |last1=Naudé |first1=Charles F. |last2=Ellis |first2=Albert T. |title=On the mechanism of cavitation damage by nonhemispherical cavities in contact with a solid boundary |journal=Journal of Basic Engineering |date=1961 |volume=83 |issue=4 |pages=648–656 |doi=10.1115/1.3662286 |s2cid=11867895 |url=https://authors.library.caltech.edu/48933/1/On%20the%20Mechanism%20of%20Cavitation%20Damage%20by%20Nonhemispherical%20Cavities%20Collapsing%20in%20Contact%20With%20a%20Solid%20Boundary.pdf |archive-url=https://web.archive.org/web/20180724061708/https://authors.library.caltech.edu/48933/1/On%20the%20Mechanism%20of%20Cavitation%20Damage%20by%20Nonhemispherical%20Cavities%20Collapsing%20in%20Contact%20With%20a%20Solid%20Boundary.pdf |archive-date=2018-07-24 |url-status=live }} Available at:

In 1944, Soviet scientists Mark Iosifovich Kornfeld (1908–1993) and L. Suvorov of the Leningrad Physico-Technical Institute (now: the Ioffe Physical-Technical Institute of the Russian Academy of Sciences, St. Petersburg, Russia) proposed that during cavitation, bubbles in the vicinity of a solid surface do not collapse symmetrically; instead, a dimple forms on the bubble at a point opposite the solid surface and this dimple evolves into a jet of liquid. This jet of liquid damages the solid surface.<ref>{{cite journal |last1=Kornfeld |first1=M. |last2=Suvorov |first2=L. |title=On the destructive action of cavitation |url=https://archive.org/details/sim_journal-of-applied-physics_1944-06_15_6/page/494 |journal=Journal of Applied Physics |date=1944 |volume=15 |issue=6 |pages=495–506|doi=10.1063/1.1707461 |bibcode=1944JAP....15..495K }}</ref> This hypothesis was supported in 1951 by theoretical studies by Maurice Rattray Jr., a doctoral student at the [[California Institute of Technology]].<ref>Rattray, Maurice, Jr. (1951) [https://thesis.library.caltech.edu/1493/1/Rattray_m_1951.pdf ''Perturbation effects in cavitation bubble dynamics.''] {{Webarchive|url=https://web.archive.org/web/20161022205009/http://thesis.library.caltech.edu/1493/1/Rattray_m_1951.pdf |date=2016-10-22 }} Ph.D. thesis, California Institute of Technology (Pasadena, California, USA).</ref> Kornfeld and Suvorov's hypothesis was confirmed experimentally in 1961 by Charles F. Naudé and Albert T. Ellis, fluid dynamicists at the California Institute of Technology.<ref>{{cite journal |last1=Naudé |first1=Charles F. |last2=Ellis |first2=Albert T. |title=On the mechanism of cavitation damage by nonhemispherical cavities in contact with a solid boundary |journal=Journal of Basic Engineering |date=1961 |volume=83 |issue=4 |pages=648–656 |doi=10.1115/1.3662286 |s2cid=11867895 |url=https://authors.library.caltech.edu/48933/1/On%20the%20Mechanism%20of%20Cavitation%20Damage%20by%20Nonhemispherical%20Cavities%20Collapsing%20in%20Contact%20With%20a%20Solid%20Boundary.pdf |archive-url=https://web.archive.org/web/20180724061708/https://authors.library.caltech.edu/48933/1/On%20the%20Mechanism%20of%20Cavitation%20Damage%20by%20Nonhemispherical%20Cavities%20Collapsing%20in%20Contact%20With%20a%20Solid%20Boundary.pdf |archive-date=2018-07-24 |url-status=live }} Available at:

[https://authors.library.caltech.edu/48933/1/On%20the%20Mechanism%20of%20Cavitation%20Damage%20by%20Nonhemispherical%20Cavities%20in%20Contact%20with%20a%20Solid%20Boundary.pdf California Institute of Technology (Pasadena, California, USA).]{{Dead link|date=July 2020 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

A series of experimental investigations of the propagation of strong [[shock wave]] (SW) in a liquid with gas bubbles, which made it possible to establish the basic laws governing the process, the mechanism for the transformation of the energy of the SW, attenuation of the SW, and the formation of the structure, and experiments on the analysis of the attenuation of waves in bubble screens with different acoustic properties were begun by pioneer works of Soviet scientist prof.[[Vladilen F. Minin|V.F. Minin]] at the Institute of Hydrodynamics (Novosibirsk, Russia) in 1957–1960, who examined also the first convenient model of a screen - a sequence of alternating flat one-dimensional liquid and gas layers.<ref name="minin">{{cite journal| last1=Shipilov| first1=S.E.| last2=Yakubov| first2=V.P.| title=History of technical protection. 60 years in science: to the jubilee of Prof. V.F. Minin| journal=IOP Conf. Series: Materials Science and Engineering| publisher=[[IOP Publishing]]| volume=363| issue=12033| date=2018| ~~page~~=012033| doi=10.1088/1757-899X/363/1/012033| bibcode=2018MS&E..363a2033S| doi-access=free}}</ref> In an experimental investigations of the dynamics of the form of pulsating gaseous cavities and interaction of SW with bubble clouds in 1957–1960 [[Vladilen F. Minin|V.F. Minin]] discovered that under the action of SW a bubble collapses asymmetrically with the formation of a cumulative jet, which forms in the process of collapse and causes fragmentation of the bubble.<ref name="minin" />

A series of experimental investigations of the propagation of strong [[shock wave]] (SW) in a liquid with gas bubbles, which made it possible to establish the basic laws governing the process, the mechanism for the transformation of the energy of the SW, attenuation of the SW, and the formation of the structure, and experiments on the analysis of the attenuation of waves in bubble screens with different acoustic properties were begun by pioneer works of Soviet scientist prof.[[Vladilen F. Minin|V.F. Minin]] at the Institute of Hydrodynamics (Novosibirsk, Russia) in 1957–1960, who examined also the first convenient model of a screen - a sequence of alternating flat one-dimensional liquid and gas layers.<ref name="minin">{{cite journal| last1=Shipilov| first1=S.E.| last2=Yakubov| first2=V.P.| title=History of technical protection. 60 years in science: to the jubilee of Prof. V.F. Minin| journal=IOP Conf. Series: Materials Science and Engineering| publisher=[[IOP Publishing]]| volume=363| issue=12033| date=2018| article-number=012033| doi=10.1088/1757-899X/363/1/012033| bibcode=2018MS&E..363a2033S| doi-access=free}}</ref> In an experimental investigations of the dynamics of the form of pulsating gaseous cavities and interaction of SW with bubble clouds in 1957–1960 [[Vladilen F. Minin|V.F. Minin]] discovered that under the action of SW a bubble collapses asymmetrically with the formation of a cumulative jet, which forms in the process of collapse and causes fragmentation of the bubble.<ref name="minin" />

==See also==

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* {{annotated link|Cavitation modelling}}

* {{annotated link|Erosion corrosion of copper water tubes}}

* {{annotated link|~~Rayleigh-Plesset~~ equation}}

* {{annotated link|Rayleigh–Plesset equation}}

* {{annotated link|Sonoluminescence}}

* {{annotated link|Supercavitation}}

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* For cavitation in plants, see ''Plant Physiology'' by Taiz and Zeiger.

* For cavitation in the engineering field, visit [http://www.corrosion-doctors.org/Forms-cavitation/cavitation.htm Cavitation corrosion] {{Webarchive|url=https://web.archive.org/web/20070624004920/http://www.corrosion-doctors.org/Forms-cavitation/cavitation.htm |date=2007-06-24 }}

* {{cite journal | last1 = Kornfelt | first1 = M. | year = 1944 | title = On the destructive action of cavitation | journal = Journal of Applied Physics | volume = 15 | issue = 6| pages = 495–506 | bibcode = 1944JAP....15..495K | doi = 10.1063/1.1707461 }}

* {{cite journal | last1 = Kornfelt | first1 = M. | year = 1944 | title = On the destructive action of cavitation | url = https://archive.org/details/sim_journal-of-applied-physics_1944-06_15_6/page/494 | journal = Journal of Applied Physics | volume = 15 | issue = 6| pages = 495–506 | bibcode = 1944JAP....15..495K | doi = 10.1063/1.1707461 }}

* For hydrodynamic cavitation in the ethanol field, visit [http://www.arisdyne.com/ Arisdyne] {{Webarchive|url=https://web.archive.org/web/20130710201353/http://www.arisdyne.com/ |date=2013-07-10 }} and Ethanol Producer Magazine: "Tiny Bubbles to Make You Happy" [http://www.ethanolproducer.com/article.jsp?article_id=5732&q=tiny%20bubbles&category_id=46]{{Dead link|date=August 2023 |bot=InternetArchiveBot |fix-attempted=yes }}

* {{cite journal | last1 = Barnett | first1 = S. | year = 1998 | title = Nonthermal issues: Cavitation—Its nature, detection and measurement; | journal = Ultrasound in Medicine & Biology | volume = 24 | pages = S11–S21 | doi=10.1016/s0301-5629(98)00074-x}}

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* [~~http~~://cav.safl.umn.edu/ Cavitation and Bubbly Flows, Saint Anthony Falls Laboratory, University of Minnesota]

* [https://cav.safl.umn.edu/ Cavitation and Bubbly Flows, Saint Anthony Falls Laboratory, University of Minnesota]

* [https://web.archive.org/web/20060206151508/http://caltechbook.library.caltech.edu/1/04/bubble.htm Cavitation and Bubble Dynamics by Christopher E. Brennen]

* [https://web.archive.org/web/20060324065024/http://caltechbook.library.caltech.edu/51/01/multiph.htm Fundamentals of Multiphase Flow by Christopher E. Brennen]

@@ Line 4: / Line 4: @@
 {{expert needed|Physics|date=July 2023|reason=Several usages of the term appear to be mixed up|talk=Meaning and scope}}
 [[File:cavitating-prop.jpg|thumb|upright=1|right|Cavitating propeller model in a [[Water tunnel (hydrodynamic)|water tunnel]] experiment]]
+{{Mechanical failure modes}}
 [[File:Cavitation.jpg|thumb|upright=1|Cavitation damage on a valve plate for an [[Axial piston pump|axial piston]] [[hydraulic pump]]]]
 [[File:Cavitation in a gear pump.ogv|thumb|upright=1|This video shows cavitation in a [[gear pump]]]]
 [[File:Cavitation Propeller Damage.JPG|right|thumb|upright=1|Cavitation damage evident on the propeller of a personal watercraft]]
-'''Cavitation''' in [[fluid mechanics]] and engineering normally is the phenomenon in which the static [[pressure]] of a liquid reduces to below the liquid's [[vapor pressure]], leading to the formation of small vapor-filled cavities in the liquid.<ref>{{cite web | url=https://metro.co.uk/2019/04/18/us-navy-secretly-designed-super-fast-futuristic-aircraft-resembling-ufo-documents-reveal-9246755/ | title=The US Navy secretly designed a super-fast futuristic aircraft resembling a UFO | date=April 18, 2019 }}</ref> When subjected to higher pressure, these cavities, called "bubbles" or "voids", collapse and can generate [[shock wave]]s that may damage machinery. These shock waves are strong when they are very close to the imploded bubble, but rapidly weaken as they propagate away from the implosion. Cavitation is a significant cause of wear in some [[engineering]] contexts. Collapsing voids that implode near to a metal surface cause [[cyclic stress]] through repeated implosion. This results in surface fatigue of the metal, causing a type of wear also called "cavitation". The most common examples of this kind of wear are to pump [[impeller]]s, and bends where a sudden change in the direction of liquid occurs.
+'''Cavitation''' in [[fluid mechanics]] and engineering normally is the phenomenon in which the static [[pressure]] of a liquid reduces to below the liquid's [[vapor pressure]], leading to the formation of small vapor-filled cavities in the liquid.<ref>{{cite web | url=https://metro.co.uk/2019/04/18/us-navy-secretly-designed-super-fast-futuristic-aircraft-resembling-ufo-documents-reveal-9246755/ | title=The US Navy secretly designed a super-fast futuristic aircraft resembling a UFO | date=April 18, 2019 }}</ref> When subjected to higher pressure, these cavities, called "bubbles" or "voids", collapse and can generate [[shock wave]]s that may damage machinery. As a concrete [[propeller]] example: The pressure on the suction side of the propeller blades can be very low and when the pressure falls to that of the vapour pressure of the working liquid, cavities filled with gas vapour can form. The process of the formation of these cavities is referred to as cavitation. If the cavities move into the regions of higher pressure (lower velocity), they will implode or collapse. These shock waves are strong when they are very close to the imploded bubble, but rapidly weaken as they propagate away from the implosion. Cavitation collapse is therefore a significant cause of wear in some [[engineering]] contexts. Collapsing voids that implode near to a hard surface cause [[cyclic stress]] through repeated implosion. This results in surface fatigue of the material, causing a type of damage also called "cavitation damage" or "cavitation erosion". The most common examples of this kind of wear are to pump [[impeller]]s, and pipe bends where a sudden change in the direction of fast moving liquid occurs.
-Cavitation is usually divided into two classes of behavior. ''Inertial (or transient) cavitation'' is the process in which a void or bubble in a liquid rapidly collapses, producing a [[shock wave]]. It occurs in nature in the strikes of [[mantis shrimp]] and [[pistol shrimp]], as well as in the [[vascular tissue]]s of plants. In manufactured objects, it can occur in [[control valves]], [[pump]]s, [[propeller]]s and [[impeller]]s.<ref>{{cite journal | doi=10.3390/fluids5040243 | doi-access=free | title=Impact of Leading Edge Roughness in Cavitation Simulations around a Twisted Foil | date=2020 | last1=Asnaghi | first1=Abolfazl | last2=Bensow | first2=Rickard E. | journal=Fluids | volume=5 | issue=4 | page=243 | bibcode=2020Fluid...5..243A }}</ref><ref>{{Cite journal |last=Paun, Viorel-Puiu & Patrascoiu, Constantin |date=2010-01-03 |title=Ideal Cavitation Erosion Process and Characteristic Erosion Curves. |url=https://www.researchgate.net/publication/356503796 |journal=Revista de Chimie -Bucharest- Original Edition |volume=61 |issue=3 |pages=281 |via=Research Gate}}</ref>
+Cavitation is usually divided into two classes of behavior. ''Inertial (or transient) cavitation'' is the process in which a void or bubble in a liquid rapidly collapses, producing a [[shock wave]]. It occurs in nature in the strikes of [[mantis shrimp]] and [[pistol shrimp]], as well as in the [[vascular tissue]]s of plants. In manufactured objects, it can occur in [[control valves]], [[pump]]s, [[propeller]]s and [[impeller]]s.<ref>{{cite journal | doi=10.3390/fluids5040243 | doi-access=free | title=Impact of Leading Edge Roughness in Cavitation Simulations around a Twisted Foil | date=2020 | last1=Asnaghi | first1=Abolfazl | last2=Bensow | first2=Rickard E. | journal=Fluids | volume=5 | issue=4 | page=243 | bibcode=2020Fluid...5..243A }}</ref><ref>{{Cite journal |last=Paun, Viorel-Puiu & Patrascoiu, Constantin |date=2010-01-03 |title=Ideal Cavitation Erosion Process and Characteristic Erosion Curves. |url=https://www.researchgate.net/publication/356503796 |journal=Revista de Chimie -Bucharest- Original Edition |volume=61 |issue=3 |page=281 |via=Research Gate}}</ref>
 ''Non-inertial cavitation'' is the process in which a bubble in a fluid is forced to oscillate in size or shape due to some form of energy input, such as an [[Sound|acoustic field]]. The gas in the bubble may contain a portion of a different gas than the vapor phase of the liquid. Such cavitation is often employed in [[ultrasonic cleaning]] baths and can also be observed in pumps, propellers, etc.
-Since the shock waves formed by collapse of the voids are strong enough to cause significant damage to parts, cavitation is typically an undesirable phenomenon in machinery. It may be desirable if intentionally used, for example, to sterilize contaminated surgical instruments, break down pollutants in water purification systems, [[emulsify]] tissue for cataract surgery or kidney stone [[lithotripsy]], or [[homogenize]] fluids. It is very often specifically prevented in the design of machines such as turbines or propellers, and eliminating cavitation is a major field in the study of [[fluid dynamics]]. However, it is sometimes useful and does not cause damage when the bubbles collapse away from machinery, such as in [[supercavitation]].
+Since the shock waves formed by collapse of the voids are strong enough to cause significant damage to parts, cavitation is typically an undesirable phenomenon in machinery. It may be desirable if intentionally used, for example, to sterilize contaminated surgical instruments, break down pollutants in water purification systems, [[emulsify]] tissue for cataract surgery or kidney stone [[lithotripsy]], or [[homogenize]] fluids. It is very often specifically prevented in the design of machines such as turbines or propellers, and eliminating cavitation is a major field in the study of [[fluid dynamics]]. However, it is sometimes useful and does not cause damage when the bubbles collapse away from machinery surfaces, such as in [[supercavitation]].
 == Physics ==
@@ Line 22: / Line 23: @@
 [[Vapor]] gases evaporate into the cavity from the surrounding medium; thus, the cavity is not a vacuum at all, but rather a low-pressure vapor (gas) bubble. Once the conditions which caused the bubble to form are no longer present, such as when the bubble moves downstream, the surrounding liquid begins to implode due its higher pressure, building up momentum as it moves inward. As the bubble finally collapses, the inward momentum of the surrounding liquid causes a sharp increase of pressure and temperature of the vapor within. The bubble eventually collapses to a minute fraction of its original size, at which point the gas within dissipates into the surrounding liquid via a rather violent mechanism which releases a significant amount of energy in the form of an acoustic shock wave and as [[sonoluminescence|visible light]]. At the point of total collapse, the temperature of the vapor within the bubble may be several thousand [[Kelvin]], and the pressure several hundred atmospheres.<ref>{{cite journal|journal=Environmental Health Perspectives|volume=64|pages=233–252|date=1985|title=Free radical generation by ultrasound in aqueous and nonaqueous solutions|last1=Riesz|first1=P.|first2=D.|last2=Berdahl|first3=C.L.|last3=Christman|pmc=1568618|doi=10.2307/3430013|pmid=3007091|jstor=3430013}}</ref>
-The physical process of cavitation inception is similar to [[boiling]]. The major difference between the two is the [[thermodynamic]] paths that precede the formation of the vapor. Boiling occurs when the local temperature of the liquid reaches the [[saturation temperature]], and further heat is supplied to allow the liquid to sufficiently [[phase transition|phase change]] into a gas. Cavitation inception occurs when the local pressure falls sufficiently far below the saturated vapor pressure, a value given by the tensile strength of the liquid at a certain temperature.<ref>{{cite web|last1=Brennen|first1=Christopher |title=Cavitation and Bubble Dynamics|publisher=Oxford University Press|pages=21 |url=http://authors.library.caltech.edu/25017/1/cavbubdynam.pdf |archive-url=https://web.archive.org/web/20121004094948/http://authors.library.caltech.edu/25017/1/cavbubdynam.pdf |archive-date=2012-10-04 |url-status=live|access-date=27 February 2015}}</ref>
+The physical process of cavitation inception is similar to [[boiling]]. The major difference between the two is the [[thermodynamic]] paths that precede the formation of the vapor. Boiling occurs when the local temperature of the liquid reaches the [[saturation temperature]], and further heat is supplied to allow the liquid to sufficiently [[phase transition|phase change]] into a gas. Cavitation inception occurs when the local pressure falls sufficiently far below the saturated vapor pressure, a value given by the tensile strength of the liquid at a certain temperature.<ref>{{cite web|last1=Brennen|first1=Christopher |title=Cavitation and Bubble Dynamics|publisher=Oxford University Press|page=21 |url=http://authors.library.caltech.edu/25017/1/cavbubdynam.pdf |archive-url=https://web.archive.org/web/20121004094948/http://authors.library.caltech.edu/25017/1/cavbubdynam.pdf |archive-date=2012-10-04 |url-status=live|access-date=27 February 2015}}</ref>
-In order for cavitation inception to occur, the cavitation "bubbles" generally need a surface on which they can [[nucleation|nucleate]]. This surface can be provided by the sides of a container, by [[impurity|impurities]] in the liquid, or by small undissolved microbubbles within the liquid. It is generally accepted that [[hydrophobe|hydrophobic]] surfaces stabilize small bubbles. These pre-existing bubbles start to grow unbounded when they are exposed to a pressure below the threshold pressure, termed Blake's threshold.<ref>{{cite book|vauthors=Postema M, de Jong N, Schmitz G|title=IEEE Ultrasonics Symposium, 2005 |chapter=Shell rupture threshold, fragmentation threshold, blake threshold |date=Sep 2005|volume=3 |location=Rotterdam, Netherlands|pages=1708–1711|doi=10.1109/ULTSYM.2005.1603194|isbn=0-7803-9382-1 |s2cid=5683516 |chapter-url=https://hal.archives-ouvertes.fr/hal-03193373/document}}</ref> The presence of an incompressible core inside a cavitation nucleus substantially lowers the cavitation threshold below the Blake threshold.<ref>{{cite journal|vauthors=Carlson CS, Matsumoto R, Fushino K, Shinzato M, Kudo N, Postema M|title=Nucleation threshold of carbon black ultrasound contrast agent|journal=Japanese Journal of Applied Physics|year=2021|volume=60|issue=SD|pages=SDDA06|doi=10.35848/1347-4065/abef0f|bibcode=2021JaJAP..60DDA06C |s2cid=233539493 |url=https://hal.archives-ouvertes.fr/hal-03192654/document|doi-access=free}}</ref>
+In order for cavitation inception to occur, the cavitation "bubbles" generally need a surface on which they can [[nucleation|nucleate]]. This surface can be provided by the sides of a container, by [[impurity|impurities]] in the liquid, or by small undissolved microbubbles within the liquid. It is generally accepted that [[hydrophobe|hydrophobic]] surfaces stabilize small bubbles. These pre-existing bubbles start to grow unbounded when they are exposed to a pressure below the threshold pressure, termed Blake's threshold.<ref>{{cite book|vauthors=Postema M, de Jong N, Schmitz G|title=IEEE Ultrasonics Symposium, 2005 |chapter=Shell rupture threshold, fragmentation threshold, blake threshold |date=Sep 2005|volume=3 |location=Rotterdam, Netherlands|pages=1708–1711|doi=10.1109/ULTSYM.2005.1603194|isbn=0-7803-9382-1 |s2cid=5683516 |url=https://hal.science/hal-03193373 |chapter-url=https://hal.archives-ouvertes.fr/hal-03193373/document}}</ref> The presence of an incompressible core inside a cavitation nucleus substantially lowers the cavitation threshold below the Blake threshold.<ref>{{cite journal|vauthors=Carlson CS, Matsumoto R, Fushino K, Shinzato M, Kudo N, Postema M|title=Nucleation threshold of carbon black ultrasound contrast agent|journal=Japanese Journal of Applied Physics|year=2021|volume=60|issue=SD|pages=SDDA06|doi=10.35848/1347-4065/abef0f|bibcode=2021JaJAP..60DDA06C |s2cid=233539493 |url=https://hal.archives-ouvertes.fr/hal-03192654/document|doi-access=free}}</ref>
 The vapor pressure here differs from the meteorological definition of vapor pressure, which describes the partial pressure of water in the atmosphere at some value less than 100% saturation. Vapor pressure as relating to cavitation refers to the vapor pressure in equilibrium conditions and can therefore be more accurately defined as the equilibrium (or saturated) [[vapor pressure]].
@@ Line 33: / Line 34: @@
 ===Hydrodynamic cavitation===
-Hydrodynamic cavitation is the process of vaporisation, bubble generation and bubble implosion which occurs in a flowing liquid as a result of a decrease and subsequent increase in local pressure. Cavitation will only occur if the local pressure declines to some point below the saturated [[vapor pressure]] of the liquid and subsequent recovery above the vapor pressure. If the recovery pressure is not above the vapor pressure then flashing is said to have occurred. In pipe systems, cavitation typically occurs either as the result of an increase in the kinetic energy (through an area constriction) or an increase in the pipe elevation.
+Hydrodynamic cavitation is the process of vaporisation, bubble generation and bubble implosion which occurs in a flowing liquid as a result of a decrease and subsequent increase in local pressure. Cavitation will only occur if the local pressure declines to some point below the saturated [[vapor pressure]] of the liquid and subsequent recovery above the vapor pressure. If the recovery pressure is not above the vapor pressure then flashing is said to have occurred.{{cn|date=September 2025}}{{clarify|how is this cavitation?|date=September 2025}} In pipe systems, cavitation typically occurs either as the result of an increase in the kinetic energy (through an area constriction) or an increase in the pipe elevation.
-Hydrodynamic cavitation can be produced by passing a liquid through a constricted channel at a specific [[flow velocity]] or by mechanical rotation of an object through a liquid.  In the case of the constricted channel and based on the specific (or unique) geometry of the system, the combination of pressure and kinetic energy can create the hydrodynamic cavitation cavern downstream of the local constriction generating high energy cavitation bubbles.
+Hydrodynamic cavitation can be produced by passing a liquid through a constricted channel at a specific [[flow velocity]] or by mechanical rotation{{clarify|Why specifically rotation?|date=September 2025}} of an object through a liquid.  In the case of the constricted channel and based on the specific (or unique) geometry of the system, the combination of pressure and kinetic energy can create the hydrodynamic cavitation cavern downstream of the local constriction generating high energy cavitation bubbles.
-Based on the thermodynamic phase change diagram, an increase in temperature could initiate a known phase change mechanism known as boiling. However, a decrease in static pressure could also help one pass the multi-phase diagram and initiate another phase change mechanism known as cavitation. On the other hand, a local increase in flow velocity could lead to a static pressure drop to the critical point at which cavitation could be initiated (based on Bernoulli's principle). The critical pressure point is vapor saturated pressure. In a closed fluidic system where no flow leakage is detected, a decrease in cross-sectional area would lead to velocity increment and hence static pressure drop. This is the working principle of many hydrodynamic cavitation based reactors for different applications such as water treatment, energy harvesting, heat transfer enhancement, food processing, etc.<ref>{{Cite journal |last1=Gevari|first1=Moein Talebian|last2=Abbasiasl|first2=Taher|last3=Niazi|first3=Soroush|last4=Ghorbani |first4=Morteza|last5=Koşar|first5=Ali|date=2020-05-05|title=Direct and indirect thermal applications of hydrodynamic and acoustic cavitation: A review|journal=Applied Thermal Engineering|volume=171|pages=115065 |doi=10.1016/j.applthermaleng.2020.115065|bibcode=2020AppTE.17115065G |s2cid=214446752|issn=1359-4311}}</ref>
+Based on the thermodynamic phase change diagram, an increase in temperature could initiate a known phase change mechanism known as boiling. However, a decrease in static pressure could also help one pass the multi-phase diagram{{clarify|"pass the multi-phase diagram"? what does this mean?, and who is the one it helps?|date=September 2025}} and initiate another phase change mechanism known as cavitation. On the other hand, a local increase in flow velocity could lead to a static pressure drop to the critical point at which cavitation could be initiated (based on Bernoulli's principle). The critical pressure point is vapor saturated pressure. In a closed fluidic system where no flow leakage is detected, a decrease in cross-sectional area would lead to velocity increment and hence static pressure drop. This is the working principle of many hydrodynamic cavitation based reactors for different applications such as water treatment, energy harvesting, heat transfer enhancement, food processing, etc.<ref>{{Cite journal |last1=Gevari|first1=Moein Talebian|last2=Abbasiasl|first2=Taher|last3=Niazi|first3=Soroush|last4=Ghorbani |first4=Morteza|last5=Koşar|first5=Ali|date=2020-05-05|title=Direct and indirect thermal applications of hydrodynamic and acoustic cavitation: A review|journal=Applied Thermal Engineering|volume=171|article-number=115065 |doi=10.1016/j.applthermaleng.2020.115065|bibcode=2020AppTE.17115065G |s2cid=214446752|issn=1359-4311}}</ref>
-There are different flow patterns detected as a cavitation flow progresses: inception, developed flow, supercavitation, and choked flow. Inception is the first moment that the second phase (gas phase) appears in the system. This is the weakest cavitating flow captured in a system corresponding to the highest [[cavitation number]]. When the cavities grow and becomes larger in size in the orifice or venturi structures, developed flow is recorded. The most intense cavitating flow is known as supercavitation where theoretically all the nozzle area of an orifice is filled with gas bubbles. This flow regime corresponds to the lowest cavitation number in a system. After supercavitation, the system is not capable of passing more flow. Hence, velocity does not change while the upstream pressure increase. This would lead to an increase in cavitation number which shows that choked flow occurred.<ref>{{Cite journal |last1=Gevari|first1=Moein Talebian|last2=Shafaghi|first2=Ali Hosseinpour|last3=Villanueva|first3=Luis Guillermo|last4=Ghorbani |first4=Morteza|last5=Koşar|first5=Ali|date=January 2020|title=Engineered Lateral Roughness Element Implementation and Working Fluid Alteration to Intensify Hydrodynamic Cavitating Flows on a Chip for Energy Harvesting|journal=Micromachines|volume=11|issue=1|pages=49|doi=10.3390/mi11010049|pmid=31906037|pmc=7019874|doi-access=free}}</ref>
+There are different flow patterns detected as a cavitation flow progresses: inception, developed flow, supercavitation, and choked flow. Inception is the first moment that the second phase (gas phase) appears in the system. This is the weakest cavitating flow captured in a system corresponding to the highest [[cavitation number]]. When the cavities grow and becomes larger in size in the orifice or venturi structures, developed flow is recorded. The most intense cavitating flow is known as supercavitation where theoretically all the nozzle area of an orifice is filled with gas bubbles. This flow regime corresponds to the lowest cavitation number in a system. After supercavitation, the system is not capable of passing more flow. Hence, velocity does not change while the upstream pressure increase. This would lead to an increase in cavitation number which shows that choked flow occurred.<ref>{{Cite journal |last1=Gevari|first1=Moein Talebian|last2=Shafaghi|first2=Ali Hosseinpour|last3=Villanueva|first3=Luis Guillermo|last4=Ghorbani |first4=Morteza|last5=Koşar|first5=Ali|date=January 2020|title=Engineered Lateral Roughness Element Implementation and Working Fluid Alteration to Intensify Hydrodynamic Cavitating Flows on a Chip for Energy Harvesting|journal=Micromachines|volume=11|issue=1|page=49|doi=10.3390/mi11010049|pmid=31906037|pmc=7019874|doi-access=free}}</ref>
 The process of bubble generation, and the subsequent growth and collapse of the cavitation bubbles, results in very high energy densities and in very high local temperatures and local pressures at the surface of the bubbles for a very short time.  The overall liquid medium environment, therefore, remains at ambient conditions.  When uncontrolled, cavitation is damaging; by controlling the flow of the cavitation, however, the power can be harnessed and non-destructive.  Controlled cavitation can be used to enhance chemical reactions or propagate certain unexpected reactions because free radicals are generated in the process due to disassociation of vapors trapped in the cavitating bubbles.<ref>{{cite web |last1=STOPAR |first1=DAVID |title=HYDRODYNAMIC CAVITATION |url=https://davidstopar.wixsite.com/home/hydrodynamic-cavitation |access-date=17 January 2020}}</ref>
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 Orifices and venturi are reported to be widely used for generating cavitation. A venturi has an inherent advantage over an orifice because of its smooth converging and diverging sections, such that it can generate a higher flow velocity at the throat for a given pressure drop across it. On the other hand, an orifice has an advantage that it can accommodate a greater number of holes (larger perimeter of holes) in a given cross sectional area of the pipe.<ref>{{cite journal |first1=Vijayanand S. |last1=Moholkar |first2=Aniruddha B. |last2=Pandit |doi=10.1002/aic.690430628 |year=1997 |title=Bubble Behavior in Hydrodynamic Cavitation: Effect of Turbulence |journal=AIChE Journal |volume=43 |issue=6 |pages=1641–1648 |bibcode=1997AIChE..43.1641M }}</ref>
-The cavitation phenomenon can be controlled to enhance the performance of high-speed marine vessels and projectiles, as well as in material processing technologies, in medicine, etc. Controlling the cavitating flows in liquids can be achieved only by advancing the mathematical foundation of the cavitation processes. These processes are manifested in different ways, the most common ones and promising for control being bubble cavitation and supercavitation. The first exact classical solution should perhaps be credited to the well-known solution by [[Hermann von Helmholtz]] in 1868.<ref>{{cite journal |last1=Helmholtz |first1=Hermann von |title=Über diskontinuierliche Flüssigkeits-Bewegungen |journal=Monatsberichte der Königlichen Preussische Akademie des Wissenschaften zu Berlin (Monthly Reports of the Royal Prussian Academy of Sciences at Berlin) |date=1868 |volume=23 |pages=215–228 |url=https://www.biodiversitylibrary.org/item/111036#page/223/mode/1up |trans-title=On discontinuous motions of fluids |language=de}}</ref> The earliest distinguished studies of academic type on the theory of a cavitating flow with free boundaries and supercavitation were published in the book ''Jets, wakes and cavities''<ref>Birkhoff, G, Zarantonello. E (1957) Jets, wakes and cavities. New York: Academic Press.  406p.</ref>  followed by ''Theory of jets of ideal fluid''.<ref>Gurevich, MI (1978) Theory of jets of ideal fluid.  Nauka, Moscow, 536p. (in Russian)</ref> Widely used in these books was the well-developed theory of conformal mappings of functions of a complex variable, allowing one to derive a large number of exact solutions of plane problems. Another venue combining the existing exact solutions with approximated and heuristic models was explored in the work ''Hydrodynamics of Flows with Free Boundaries''<ref>Logvinovich, GV (1969) Hydrodynamics of Flows with Free Boundaries. Naukova dumka, Kiev, 215p. (In Russian)</ref>  that refined the applied calculation techniques based on the principle of cavity expansion independence, theory of pulsations and stability of elongated axisymmetric cavities, etc.<ref>Knapp, RT, Daili, JW, Hammit, FG (1970) Cavitation. New York: Mc Graw Hill Book Company.  578p.</ref> and in ''Dimensionality and similarity methods in the problems of the hydromechanics of vessels''.<ref>Epshtein, LA (1970) Dimensionality and similarity methods in the problems of the hydromechanics of vessels. Sudostroyenie, Leningrad, 208p. (In Russian)</ref>
+The cavitation phenomenon can be controlled to enhance the performance of high-speed marine vessels and projectiles, as well as in material processing technologies, in medicine, etc. Controlling the cavitating flows in liquids can be achieved only by advancing the mathematical foundation of the cavitation processes. These processes are manifested in different ways, the most common ones and promising for control being bubble cavitation and supercavitation. The first exact classical solution should perhaps be credited to the well-known solution by [[Hermann von Helmholtz]] in 1868.<ref>{{cite journal |last1=Helmholtz |first1=Hermann von |title=Über diskontinuierliche Flüssigkeits-Bewegungen |journal=Monatsberichte der Königlichen Preussische Akademie des Wissenschaften zu Berlin (Monthly Reports of the Royal Prussian Academy of Sciences at Berlin) |date=1868 |volume=23 |pages=215–228 |url=https://www.biodiversitylibrary.org/item/111036#page/223/mode/1up |trans-title=On discontinuous motions of fluids |language=de}}</ref> The earliest distinguished studies of academic type on the theory of a cavitating flow with free boundaries and supercavitation were published in the book ''Jets, wakes and cavities''<ref>[[Garrett Birkhoff|Birkhoff, G]], Zarantonello. E (1957) Jets, wakes and cavities. New York: Academic Press.  406p.</ref>  followed by ''Theory of jets of ideal fluid''.<ref>Gurevich, MI (1978) Theory of jets of ideal fluid.  Nauka, Moscow, 536p. (in Russian)</ref> Widely used in these books was the well-developed theory of conformal mappings of functions of a complex variable, allowing one to derive a large number of exact solutions of plane problems. Another venue combining the existing exact solutions with approximated and heuristic models was explored in the work ''Hydrodynamics of Flows with Free Boundaries''<ref>Logvinovich, GV (1969) Hydrodynamics of Flows with Free Boundaries. Naukova dumka, Kiev, 215p. (In Russian)</ref>  that refined the applied calculation techniques based on the principle of cavity expansion independence, theory of pulsations and stability of elongated axisymmetric cavities, etc.<ref>Knapp, RT, Daili, JW, Hammit, FG (1970) Cavitation. New York: Mc Graw Hill Book Company.  578p.</ref> and in ''Dimensionality and similarity methods in the problems of the hydromechanics of vessels''.<ref>Epshtein, LA (1970) Dimensionality and similarity methods in the problems of the hydromechanics of vessels. Sudostroyenie, Leningrad, 208p. (In Russian)</ref>
 A natural continuation of these studies was recently presented in ''The Hydrodynamics of Cavitating Flows''<ref>Terentiev, A, Kirschner, I, Uhlman, J, (2011) The Hydrodynamics of Cavitating Flows. Backbone Publishing Company, 598pp.</ref>  – an encyclopedic work encompassing all the best advances in this domain for the last three decades, and blending the classical methods of mathematical research with the modern capabilities of computer technologies. These include elaboration of nonlinear numerical methods of solving 3D cavitation problems, refinement of the known plane linear theories, development of asymptotic theories of axisymmetric and nearly axisymmetric flows, etc. As compared to the classical approaches, the new trend is characterized by expansion of the theory into the 3D flows. It also reflects a certain correlation with current works of an applied character on the hydrodynamics of supercavitating bodies.
@@ Line 57: / Line 58: @@
 Ultrasonic cavitation inception will occur when the acceleration of the ultrasound source is enough to produce the needed pressure drop. This pressure drop depends on the value of the acceleration and the size of the affected volume by the pressure wave. The dimensionless number that predicts ultrasonic cavitation is the [[cavitation number|Garcia-Atance number]]. High power ultrasonic horns produce accelerations high enough to create a cavitating region that can be used for [[Homogenization (chemistry)|homogenization]], [[Dispersion (chemistry)|dispersion]], deagglomeration, erosion, cleaning, milling, [[emulsion|emulsification]], extraction, disintegration, and [[sonochemistry]].
-===Aerodyamic cavitation===
-Although predominant in liquids, cavitation exists to an extent in gas as it has fluid dynamics at high speeds.<ref>{{Cite web|url=https://www.researchgate.net/figure/Asymmetric-electrode-arrangement-of-an-aerodynamic-plasma-actuator_fig1_253041135|title=Asymmetric electrode arrangement of an aerodynamic plasma actuator. &#124; Download Scientific Diagram}}</ref><ref>{{Cite web|url=https://www.researchgate.net/publication/301889798|title=Simultaneous Investigation of Flexibility and Plasma Actuation Effects on the Aerodynamic Characteristics of an Oscillating Airfoil}}</ref> For example, a [[bullet]] with a flat tip moves faster underwater as it creates cavitation compared to a bullet with a sharp tip. A [[dune]] shape is very useful for managing aerodynamic cavitation.  The shape of a dune provides minimal resistance to the wind. With small dunes installed on the surfaces of aircraft and other high speed vehicles, friction against the air decreases by several times. The dune surface pushes the air upwards, underneath and behind areas where the air pressure drops, reducing friction. The dune may increase frontal resistance, but that will be compensated for by a decrease in the total friction area, as also happens with an underwater bullet. As a result, the speed of the aircraft or vehicle will increase significantly.<ref>{{cite web | url=https://contest.techbriefs.com/2019/entries/aerospace-and-defense/9431#:~:text=Contrary%20to%20logic%20and%20general,the%20bullet%20surface%20very%20slightly | title=Aerodynamic Cavitation for Aircraft }}</ref>
 ==Applications==
+===Water transport===
+In [[supercavitation]], cavitation is intentionally induced around high-speed submerged objects to reduce [[skin drag]].
 ===Chemical engineering===
-In industry, cavitation is often used to [[Homogenization (chemistry)|homogenize]], or mix and break down, suspended particles in a [[colloidal]] liquid compound such as paint mixtures or milk. Many industrial mixing machines are based upon this design principle. It is usually achieved through impeller design or by forcing the mixture through an annular opening that has a narrow entrance orifice with a much larger exit orifice. In the latter case, the drastic decrease in pressure as the liquid accelerates into a larger volume induces cavitation. This method can be controlled with [[hydraulic]] devices that control inlet orifice size, allowing for dynamic adjustment during the process, or modification for different substances. The surface of this type of mixing valve, against which surface the cavitation bubbles are driven causing their implosion, undergoes tremendous mechanical and thermal localized stress; they are therefore often constructed of extremely strong and hard materials such as [[stainless steel]], [[Stellite]], or even [[polycrystalline diamond]] (PCD).
+In industry, cavitation is often used to [[Homogenization (chemistry)|homogenize]], or mix and break down, suspended particles in a [[colloidal]] liquid compound such as paint mixtures or milk. Many industrial mixing machines are based upon this design principle. It is usually achieved through impeller design or by forcing the mixture through an annular opening that has a narrow entrance orifice with a much larger exit orifice. In the latter case, the drastic decrease in pressure as the liquid accelerates into a larger volume induces cavitation. This method can be controlled with [[hydraulic]] devices that control inlet orifice size, allowing for dynamic adjustment during the process, or modification for different substances. The surface of this type of mixing valve, against which surface the cavitation bubbles are driven causing their implosion, undergoes tremendous mechanical and thermal localized stress; they are therefore often constructed of extremely strong and hard materials such as [[stainless steel]], [[Stellite]], or even [[polycrystalline diamond]] (PCD).{{cn|date=September 2025}}<!--plausible but not obvious-->
-Cavitating [[water purification]] devices have also been designed, in which the extreme conditions of cavitation can break down pollutants and organic molecules. Spectral analysis of light emitted in [[sonochemistry|sonochemical reactions]] reveal chemical and plasma-based mechanisms of energy transfer. The light emitted from cavitation bubbles is termed [[sonoluminescence]].
+Cavitating [[water purification]] devices have also been designed, in which the extreme conditions of cavitation can break down pollutants and organic molecules. Spectral analysis of light emitted in [[sonochemistry|sonochemical reactions]] reveal chemical and plasma-based mechanisms of energy transfer. The light emitted from cavitation bubbles is termed [[sonoluminescence]].{{cn|date=September 2025}}<!--plausible but not obvious-->
-Use of this technology has been tried successfully in alkali refining of vegetable oils.<ref>{{cite web|url=http://www.ctinanotech.com/technology/edible-oil-refining|title=Edible Oil Refining|publisher=Cavitation Technologies, Inc.|access-date=2016-01-04|archive-date=2016-01-29 |archive-url=https://web.archive.org/web/20160129081235/http://www.ctinanotech.com/technology/edible-oil-refining|url-status=dead}}</ref><!-- Site down on 2016-01-07, but Google cache works. -->
+Use of this technology has been tried successfully in alkali refining of vegetable oils.<ref>{{cite web|url=http://www.ctinanotech.com/technology/edible-oil-refining|title=Edible Oil Refining|publisher=Cavitation Technologies, Inc.|access-date=2016-01-04|archive-date=2016-01-29 |archive-url=https://web.archive.org/web/20160129081235/http://www.ctinanotech.com/technology/edible-oil-refining}}</ref><!-- Site down on 2016-01-07, but Google cache works. -->
-Hydrophobic chemicals are attracted underwater by cavitation as the pressure difference between the bubbles and the liquid water forces them to join. This effect may assist in [[protein folding]].<ref>{{cite web | url = http://www.sandia.gov/news/resources/releases/2006/snap.html | website = Sandia National Laboratories | date = 2006-08-02 | access-date = 2007-10-17 | title = Sandia researchers solve mystery of attractive surfaces | archive-date = 2007-10-17 | archive-url = https://web.archive.org/web/20071017163015/http://sandia.gov/news/resources/releases/2006/snap.html | url-status = dead }}</ref>
+Hydrophobic chemicals are attracted underwater by cavitation as the pressure difference between the bubbles and the liquid water forces them to join. This effect may assist in [[protein folding]].<ref>{{cite web | url = http://www.sandia.gov/news/resources/releases/2006/snap.html | website = Sandia National Laboratories | date = 2006-08-02 | access-date = 2007-10-17 | title = Sandia researchers solve mystery of attractive surfaces | archive-date = 2007-10-17 | archive-url = https://web.archive.org/web/20071017163015/http://sandia.gov/news/resources/releases/2006/snap.html }}</ref>
 ===Biomedical===
 Cavitation plays an important role for the destruction of [[kidney stone]]s in [[extracorporeal shock wave lithotripsy|shock wave lithotripsy]].<ref>{{Cite journal|pmc = 2442573|year = 2003|last1 = Pishchalnikov|first1 = Y. A|title = Cavitation Bubble Cluster Activity in the Breakage of Kidney Stones by Lithotripter Shock Waves|journal = Journal of Endourology|volume = 17|issue = 7|pages = 435–446|last2 = Sapozhnikov|first2 = O. A|last3 = Bailey|first3 = M. R|last4 = Williams Jr|first4 = J. C|last5 = Cleveland|first5 = R. O|last6 = Colonius|first6 = T|last7 = Crum|first7 = L. A|last8 = Evan|first8 = A. P|last9 = McAteer|first9 = J. A|pmid = 14565872|doi = 10.1089/089277903769013568}}</ref> Currently, tests are being conducted as to whether cavitation can be used to transfer large molecules into biological [[cell (biology)|cell]]s ([[sonoporation]]). Nitrogen cavitation is a method used in research to [[lysis|lyse]] cell membranes while leaving organelles intact.
-Cavitation plays a key role in non-thermal, non-invasive fractionation of tissue for treatment of a variety of diseases<ref>{{cite web| url = http://www.histotripsy.umich.edu/| title = University of Michigan. ''Therapeutic Ultrasound Group, Biomedical Engineering Department, University of Michigan''.}}</ref> and can be used to open the [[Blood–brain barrier|blood-brain barrier]] to increase uptake of neurological drugs in the brain.<ref>{{Cite journal | doi=10.1038/srep33264| pmid=27630037| pmc=5024096| title=Focused Ultrasound-Induced Blood-Brain Barrier Opening: Association with Mechanical Index and Cavitation Index Analyzed by Dynamic Contrast-Enhanced Magnetic-Resonance Imaging| journal=Scientific Reports| volume=6| pages=33264| year=2016| last1=Chu| first1=Po-Chun| last2=Chai| first2=Wen-Yen| last3=Tsai| first3=Chih-Hung| last4=Kang| first4=Shih-Tsung| last5=Yeh| first5=Chih-Kuang| last6=Liu| first6=Hao-Li| bibcode=2016NatSR...633264C}}</ref>
+Cavitation plays a key role in non-thermal, non-invasive fractionation of tissue for treatment of a variety of diseases<ref>{{cite web| url = https://www.histotripsy.umich.edu/| title = University of Michigan. ''Therapeutic Ultrasound Group, Biomedical Engineering Department, University of Michigan''.}}</ref> and can be used to open the [[Blood–brain barrier|blood-brain barrier]] to increase uptake of neurological drugs in the brain.<ref>{{Cite journal | doi=10.1038/srep33264| pmid=27630037| pmc=5024096| title=Focused Ultrasound-Induced Blood-Brain Barrier Opening: Association with Mechanical Index and Cavitation Index Analyzed by Dynamic Contrast-Enhanced Magnetic-Resonance Imaging| journal=Scientific Reports| volume=6| article-number=33264| year=2016| last1=Chu| first1=Po-Chun| last2=Chai| first2=Wen-Yen| last3=Tsai| first3=Chih-Hung| last4=Kang| first4=Shih-Tsung| last5=Yeh| first5=Chih-Kuang| last6=Liu| first6=Hao-Li| bibcode=2016NatSR...633264C}}</ref>
 Cavitation also plays a role in [[HIFU]], a thermal non-invasive treatment methodology for [[cancer]].<ref>{{Cite journal|last1=Rabkin|first1=Brian A.|last2=Zderic|first2=Vesna|last3=Vaezy|first3=Shahram|date=2005-07-01 |title=Hyperecho in ultrasound images of HIFU therapy: Involvement of cavitation|journal=Ultrasound in Medicine and Biology|volume=31|issue=7|pages=947–956|doi=10.1016/j.ultrasmedbio.2005.03.015|issn=0301-5629|pmid=15972200}}</ref>
-In wounds caused by high velocity impacts (like for example bullet wounds) there are also effects due to cavitation. The exact wounding mechanisms are not completely understood yet as there is temporary cavitation, and permanent cavitation together with crushing, tearing and stretching. Also the high variance in density within the body makes it hard to determine its effects.<ref>{{Cite journal|last1=Stefanopoulos |first1=Panagiotis K.|last2=Mikros |first2=George|last3=Pinialidis|first3=Dionisios E.|last4=Oikonomakis |first4=Ioannis N.|last5=Tsiatis|first5=Nikolaos E.|last6=Janzon|first6=Bo|date=2009-09-01|title=Wound ballistics of military rifle bullets: An update on controversial issues and associated misconceptions |journal=The Journal of Trauma and Acute Care Surgery|volume=87|issue=3|pages=690–698|pmid=30939579 |s2cid=92996795|doi=10.1097/TA.0000000000002290}}</ref>
+In wounds caused by high velocity impacts (like for example bullet wounds) there are also effects due to cavitation. The exact wounding mechanisms are not completely understood yet as there is temporary cavitation, and permanent cavitation {{clarify|what is permanent cavitation?|date=September 2025}} together with crushing, tearing and stretching. Also the high variance in density within the body makes it hard to determine its effects.<ref>{{Cite journal|last1=Stefanopoulos |first1=Panagiotis K.|last2=Mikros |first2=George|last3=Pinialidis|first3=Dionisios E.|last4=Oikonomakis |first4=Ioannis N.|last5=Tsiatis|first5=Nikolaos E.|last6=Janzon|first6=Bo|date=2009-09-01|title=Wound ballistics of military rifle bullets: An update on controversial issues and associated misconceptions |journal=The Journal of Trauma and Acute Care Surgery|volume=87|issue=3|pages=690–698|pmid=30939579 |s2cid=92996795|doi=10.1097/TA.0000000000002290}}</ref>
-Ultrasound sometimes is used to increase bone formation, for instance in post-surgical applications.<ref>{{cite web|url=http://www.physiomontreal.com/Ultrasound.pdf |archive-url=https://web.archive.org/web/20030309225204/http://www.physiomontreal.com/Ultrasound.pdf |archive-date=2003-03-09 |url-status=live|title=Physio Montreal Article "Ultrasound"}}</ref>
+Ultrasound sometimes is used to increase bone formation, for instance in post-surgical applications.{{clarify|what is the relevance to cavitation? Ultrasound does not imply cavitation.|date=September 2025}}<ref>{{cite web|url=http://www.physiomontreal.com/Ultrasound.pdf |archive-url=https://web.archive.org/web/20030309225204/http://www.physiomontreal.com/Ultrasound.pdf |archive-date=2003-03-09 |url-status=live|title=Physio Montreal Article "Ultrasound"}}</ref>
 It has been suggested that the sound of [[cracking joints|"cracking" knuckles]] derives from the collapse of cavitation in the [[synovial fluid]] within the joint.<ref>{{cite journal|last=Unsworth|first=A|author2=Dowson, D|author3=Wright, V|title='Cracking joints'. A bioengineering study of cavitation in the metacarpophalangeal joint|journal=Annals of the Rheumatic Diseases|date=July 1971|volume=30|issue=4|pages=348–58|pmid=5557778|doi=10.1136/ard.30.4.348|pmc=1005793}}</ref>
-Cavitation can also form [[Ozone micro-nanobubbles]] which shows promise in dental applications.<ref>{{Cite journal |last1=Hauser-Gerspach |first1=Irmgard |last2=Vadaszan |first2=Jasminka |last3=Deronjic |first3=Irma |last4=Gass |first4=Catiana |last5=Meyer |first5=Jürg |last6=Dard |first6=Michel |last7=Waltimo |first7=Tuomas |last8=Stübinger |first8=Stefan |last9=Mauth |first9=Corinna |date=2011-08-13 |title=Influence of gaseous ozone in peri-implantitis: bactericidal efficacy and cellular response. An in vitro study using titanium and zirconia |url=http://dx.doi.org/10.1007/s00784-011-0603-2 |journal=Clinical Oral Investigations |volume=16 |issue=4 |pages=1049–1059 |doi=10.1007/s00784-011-0603-2 |pmid=21842144 |s2cid=10747305 |issn=1432-6981|url-access=subscription }}</ref>
+Cavitation can also form [[Ozone micro-nanobubbles]] which shows promise in dental applications.<ref>{{Cite journal |last1=Hauser-Gerspach |first1=Irmgard |last2=Vadaszan |first2=Jasminka |last3=Deronjic |first3=Irma |last4=Gass |first4=Catiana |last5=Meyer |first5=Jürg |last6=Dard |first6=Michel |last7=Waltimo |first7=Tuomas |last8=Stübinger |first8=Stefan |last9=Mauth |first9=Corinna |date=2011-08-13 |title=Influence of gaseous ozone in peri-implantitis: bactericidal efficacy and cellular response. An in vitro study using titanium and zirconia |journal=Clinical Oral Investigations |volume=16 |issue=4 |pages=1049–1059 |doi=10.1007/s00784-011-0603-2 |pmid=21842144 |s2cid=10747305 |issn=1432-6981}}</ref>
 ===Cleaning===
@@ Line 101: / Line 101: @@
 ==== Biodiesel ====
-Cavitation has been applied to Biodiesel production since 2011 and is considered a proven and standard technology in this application. The implementation of hydrodynamic cavitation in the transesterification process allows for a significant reduction in catalyst use, quality improvement and production capacity increase.<ref>{{cite web |url=http://www.biodieselmagazine.com/articles/8457/hero-bx-adopts-cavitation-tech-to-reduce-catalyst-use-monos |access-date=2022-05-19 |author=Arisdyne Systems |date=April 27, 2012 |title=Hero BX adopts cavitation tech to reduce catalyst use, monos |work=Biodiesel Magazine}}</ref><ref>{{Cite web|url=https://patents.justia.com/patent/9000244|title=US Patent for Process for production of biodiesel Patent (Patent # 9,000,244 issued April 7, 2015) - Justia Patents Search|website=patents.justia.com}}</ref><ref>{{Cite web|url=https://patents.justia.com/patent/20100175309|title=US Patent Application for PROCESS FOR IMPROVED BIODIESEL FUEL Patent Application (Application #20100175309 issued July 15, 2010) - Justia Patents Search|website=patents.justia.com}}</ref>
+Cavitation has been applied to Biodiesel production since 2011 and is considered a proven and standard technology in this application. The implementation of hydrodynamic cavitation in the transesterification process allows for a significant reduction in catalyst use, quality improvement and production capacity increase.<ref>{{cite web |url=https://www.biodieselmagazine.com/articles/8457/hero-bx-adopts-cavitation-tech-to-reduce-catalyst-use-monos |access-date=2022-05-19 |author=Arisdyne Systems |date=April 27, 2012 |title=Hero BX adopts cavitation tech to reduce catalyst use, monos |work=Biodiesel Magazine}}</ref><ref>{{Cite web|url=https://patents.justia.com/patent/9000244|title=US Patent for Process for production of biodiesel Patent (Patent # 9,000,244 issued April 7, 2015) - Justia Patents Search|website=patents.justia.com}}</ref><ref>{{Cite web|url=https://patents.justia.com/patent/20100175309|title=US Patent Application for PROCESS FOR IMPROVED BIODIESEL FUEL Patent Application (Application #20100175309 issued July 15, 2010) - Justia Patents Search|website=patents.justia.com}}</ref>
 ==Cavitation damage{{anchor|Cavitation erosion}}==
@@ Line 124: / Line 124: @@
 [[Suction]] cavitation occurs when the pump suction is under a low-pressure/high-vacuum condition where the liquid turns into a vapor at the eye of the pump impeller. This vapor is carried over to the discharge side of the pump, where it no longer sees vacuum and is compressed back into a liquid by the discharge pressure. This imploding action occurs violently and attacks the face of the impeller. An impeller that has been operating under a suction cavitation condition can have large chunks of material removed from its face or very small bits of material removed, causing the impeller to look spongelike. Both cases will cause premature failure of the pump, often due to bearing failure. Suction cavitation is often identified by a sound like gravel or marbles in the pump casing.
-Common causes of suction cavitation can include clogged filters, pipe blockage on the suction side, poor piping design, pump running too far right on the pump curve, or conditions not meeting [[Net positive suction head|NPSH]] (net positive suction head) requirements.<ref>{{Cite news|url=https://info.triangle-pump.com/blog/pump-cavitation|title=Common Causes of Cavitation in Pumps|last=Kelton|first=Sam|date=May 16, 2017|publisher=Triangle Pump Components|access-date=2018-07-16|archive-date=2018-07-16 |archive-url=https://web.archive.org/web/20180716224100/https://info.triangle-pump.com/blog/pump-cavitation|url-status=dead}}</ref>
+Common causes of suction cavitation can include clogged filters, pipe blockage on the suction side, poor piping design, pump running too far right on the pump curve, or conditions not meeting [[Net positive suction head|NPSH]] (net positive suction head) requirements.<ref>{{Cite news|url=https://info.triangle-pump.com/blog/pump-cavitation|title=Common Causes of Cavitation in Pumps|last=Kelton|first=Sam|date=May 16, 2017|publisher=Triangle Pump Components|access-date=2018-07-16|archive-date=2018-07-16 |archive-url=https://web.archive.org/web/20180716224100/https://info.triangle-pump.com/blog/pump-cavitation}}</ref>
 In automotive applications, a clogged filter in a hydraulic system (power steering, power brakes) can cause suction cavitation making a noise that rises and falls in synch with engine RPM.  It is fairly often a high pitched whine, like set of nylon gears not quite meshing correctly.
@@ Line 136: / Line 136: @@
 Since all pumps require well-developed inlet flow to meet their potential, a pump may not perform or be as reliable as expected due to a faulty suction piping layout such as a close-coupled elbow on the inlet flange. When poorly developed flow enters the pump impeller, it strikes the vanes and is unable to follow the impeller passage. The liquid then separates from the vanes causing mechanical problems due to cavitation, vibration and performance problems due to turbulence and poor filling of the impeller. This results in premature seal, bearing and impeller failure, high maintenance costs, high power consumption, and less-than-specified head and/or flow.
-To have a well-developed flow pattern, pump manufacturer's manuals recommend about (10 diameters?) of straight pipe run upstream of the pump inlet flange. Unfortunately, piping designers and plant personnel must contend with space and equipment layout constraints and usually cannot comply with this recommendation. Instead, it is common to use an elbow close-coupled to the pump suction which creates a poorly developed flow pattern at the pump suction.<ref>{{cite web| last=Golomb| first=Richard| title=A new tailpipe design for GE frame-type gas turbines to substantially lower pressure losses |url=http://cat.inist.fr/?aModele=afficheN&cpsidt=1454644|publisher=American Society of Mechanical Engineers| access-date=2 August 2012}}</ref>
+To have a well-developed flow pattern, pump manufacturer's manuals recommend about (10 diameters?) of straight pipe run upstream of the pump inlet flange. Unfortunately, piping designers and plant personnel must contend with space and equipment layout constraints and usually cannot comply with this recommendation. Instead, it is common to use an elbow close-coupled to the pump suction which creates a poorly developed flow pattern at the pump suction.<ref>{{cite journal| last=Golomb| first=Richard| title=A new tailpipe design for GE frame-type gas turbines to substantially lower pressure losses | journal=Journal of Clinical Neuroscience| volume=7| issue=5|url=http://cat.inist.fr/?aModele=afficheN&cpsidt=1454644|publisher=American Society of Mechanical Engineers| access-date=2 August 2012}}</ref>
 With a double-suction pump tied to a close-coupled elbow, flow distribution to the impeller is poor and causes reliability and performance shortfalls. The elbow divides the flow unevenly with more channeled to the outside of the elbow. Consequently, one side of the double-suction impeller receives more flow at a higher flow velocity and pressure while the starved side receives a highly turbulent and potentially damaging flow. This degrades overall pump performance (delivered head, flow and power consumption) and causes axial imbalance which shortens seal, bearing and impeller life.<ref>[[Pulp & Paper]] (1992), Daishowa Reduces Pump Maintenance by Installing Fluid Rotating Vanes</ref>
@@ Line 174: / Line 174: @@
 ===Spore dispersal in plants===
-Cavitation plays a role in the spore dispersal mechanisms of certain plants. In [[fern]]s, for example, the fern sporangium acts as a catapult that launches spores into the air. The charging phase of the catapult is driven by water evaporation from the [[annulus (botany)|annulus]] cells, which triggers a pressure decrease. When the compressive pressure reaches approximately 9{{nbsp}}[[Pascal (unit)|MPa]], cavitation occurs. This rapid event triggers spore dispersal due to the [[elastic energy]] released by the annulus structure. The initial spore acceleration is extremely large – up to 10{{sup|5}} times the [[gravitational acceleration]].<ref name="NoblinRojas2012">{{cite journal |last1=Noblin|first1=X.|last2=Rojas|first2=N. O. |last3=Westbrook|first3=J.|last4=Llorens|first4=C.|last5=Argentina|first5=M.|last6=Dumais|first6=J. |title=The Fern Sporangium: A Unique Catapult|journal=Science|volume=335 |issue=6074|year=2012|pages=1322 |issn=0036-8075|doi=10.1126/science.1215985|pmid=22422975|bibcode=2012Sci...335.1322N|s2cid=20037857 |url=https://hal.archives-ouvertes.fr/hal-00826001/file/1215985_maintext-resumitted2-for-HAL.pdf |archive-url=https://web.archive.org/web/20190504014851/https://hal.archives-ouvertes.fr/hal-00826001/file/1215985_maintext-resumitted2-for-HAL.pdf |archive-date=2019-05-04 |url-status=live}}</ref>
+Cavitation plays a role in the spore dispersal mechanisms of certain plants. In [[fern]]s, for example, the fern sporangium acts as a catapult that launches spores into the air. The charging phase of the catapult is driven by water evaporation from the [[annulus (botany)|annulus]] cells, which triggers a pressure decrease. When the compressive pressure reaches approximately 9{{nbsp}}[[Pascal (unit)|MPa]], cavitation occurs. This rapid event triggers spore dispersal due to the [[elastic energy]] released by the annulus structure. The initial spore acceleration is extremely large – up to 10{{sup|5}} times the [[gravitational acceleration]].<ref name="NoblinRojas2012">{{cite journal |last1=Noblin|first1=X.|last2=Rojas|first2=N. O. |last3=Westbrook|first3=J.|last4=Llorens|first4=C.|last5=Argentina|first5=M.|last6=Dumais|first6=J. |title=The Fern Sporangium: A Unique Catapult|journal=Science|volume=335 |issue=6074|year=2012|page=1322 |issn=0036-8075|doi=10.1126/science.1215985|pmid=22422975|bibcode=2012Sci...335.1322N|s2cid=20037857 |url=https://hal.archives-ouvertes.fr/hal-00826001/file/1215985_maintext-resumitted2-for-HAL.pdf |archive-url=https://web.archive.org/web/20190504014851/https://hal.archives-ouvertes.fr/hal-00826001/file/1215985_maintext-resumitted2-for-HAL.pdf |archive-date=2019-05-04 |url-status=live}}</ref>
 ===Marine life===
@@ Line 181: / Line 181: @@
 Cavitation may limit the maximum swimming speed of powerful swimming animals like [[dolphins]] and [[tuna]].<ref>{{cite magazine | last = Brahic | first = Catherine | title = Dolphins swim so fast it hurts   | magazine = New Scientist | date = 2008-03-28 | url = https://www.newscientist.com/channel/life/dn13553-dolphins-swim-so-fast-it-hurts.html | access-date = 2008-03-31}}</ref> Dolphins may have to restrict their speed because collapsing cavitation bubbles on their tail are painful. Tuna have bony fins without nerve endings and do not feel pain from cavitation. They are slowed down when cavitation bubbles create a vapor film around their fins. Lesions have been found on tuna that are consistent with cavitation damage.<ref name="IosilevskiiWeihs2008">{{cite journal|last1=Iosilevskii|first1=G|last2=Weihs|first2=D|title=Speed limits on swimming of fishes and cetaceans|journal=Journal of the Royal Society Interface|volume=5|issue=20|year=2008|pages=329–338|issn=1742-5689|doi=10.1098/rsif.2007.1073|pmid=17580289|pmc=2607394}}</ref>
-Some sea animals have found ways to use cavitation to their advantage when hunting prey. The [[pistol shrimp]] snaps a specialized claw to create cavitation, which can kill small fish. The [[mantis shrimp]] (of the ''smasher'' variety) uses cavitation as well in order to stun, smash open, or kill the shellfish that it feasts upon.<ref>{{cite web|last=Patek|first=Sheila|title=Sheila Patek clocks the fastest animals|url=http://www.ted.com/talks/sheila_patek_clocks_the_fastest_animals.html|publisher=TED|access-date=18 February 2011}}</ref>
+Some sea animals have found ways to use cavitation to their advantage when hunting prey. The [[pistol shrimp]] snaps a specialized claw to create cavitation, which can kill small fish. The [[mantis shrimp]] (of the ''smasher'' variety) uses cavitation as well in order to stun, smash open, or kill the shellfish that it feasts upon.<ref>{{cite web|last=Patek|first=Sheila|title=Sheila Patek clocks the fastest animals|date=April 5, 2007 |url=https://www.ted.com/talks/sheila_patek_the_shrimp_with_a_kick|publisher=TED|access-date=18 February 2011}}</ref>
-[[Thresher sharks]] use 'tail slaps' to debilitate their small fish prey and cavitation bubbles have been seen rising from the apex of the tail arc.<ref name="TsiklirasOliver2013">{{cite journal|last1=Tsikliras|first1=Athanassios C.|last2=Oliver|first2=Simon P.|last3=Turner|first3=John R.|last4=Gann|first4=Klemens|last5=Silvosa|first5=Medel|last6=D'Urban Jackson|first6=Tim|title=Thresher Sharks Use Tail-Slaps as a Hunting Strategy|journal=PLOS ONE|volume=8|issue=7|year=2013|pages=e67380|issn=1932-6203|doi=10.1371/journal.pone.0067380|pmid=23874415|pmc=3707734|bibcode = 2013PLoSO...867380O |doi-access=free}}</ref><ref>Archived at [https://ghostarchive.org/varchive/youtube/20211205/lHoCCPsRuhg Ghostarchive]{{cbignore}} and the [https://web.archive.org/web/20130825141415/http://www.youtube.com/watch?v=lHoCCPsRuhg&gl=US&hl=en Wayback Machine]{{cbignore}}: {{cite web| url = https://www.youtube.com/watch?v=lHoCCPsRuhg| title = THRESHER SHARKS KILL PREY WITH TAIL | website=[[YouTube]]| date = July 12, 2013 }}{{cbignore}}</ref>
+[[Thresher sharks]] use 'tail slaps' to debilitate their small fish prey and cavitation bubbles have been seen rising from the apex of the tail arc.<ref name="TsiklirasOliver2013">{{cite journal|last1=Tsikliras|first1=Athanassios C.|last2=Oliver|first2=Simon P.|last3=Turner|first3=John R.|last4=Gann|first4=Klemens|last5=Silvosa|first5=Medel|last6=D'Urban Jackson|first6=Tim|title=Thresher Sharks Use Tail-Slaps as a Hunting Strategy|journal=PLOS ONE|volume=8|issue=7|year=2013|article-number=e67380|issn=1932-6203|doi=10.1371/journal.pone.0067380|pmid=23874415|pmc=3707734|bibcode = 2013PLoSO...867380O |doi-access=free}}</ref><ref>Archived at [https://ghostarchive.org/varchive/youtube/20211205/lHoCCPsRuhg Ghostarchive]{{cbignore}} and the [https://web.archive.org/web/20130825141415/http://www.youtube.com/watch?v=lHoCCPsRuhg&gl=US&hl=en Wayback Machine]{{cbignore}}: {{cite web| url = https://www.youtube.com/watch?v=lHoCCPsRuhg| title = THRESHER SHARKS KILL PREY WITH TAIL | website=[[YouTube]]| date = July 12, 2013 }}{{cbignore}}</ref>
 ===Coastal erosion===
@@ Line 190: / Line 190: @@
 == History ==
-As early as 1754, the Swiss mathematician [[Leonhard Euler]] (1707–1783) speculated about the possibility of cavitation.<ref>{{cite journal |last1=Euler |title=Théorie plus complete des machines qui sont mises en mouvement par la réaction de l'eau |journal=Mémoires de l'Académie Royale des Sciences et Belles-Lettres (Berlin) |date=1754 |volume=10 |pages=227–295 |language=fr |url=https://babel.hathitrust.org/cgi/pt?id=mdp.39015038659283;view=1up;seq=271 |trans-title=A more complete theory of machines that are set in motion by reaction against water}} See §LXXXI, pp. 266–267. From p. 266: ''"Il pourroit donc arriver que la pression en M devint même négative, & alors l'eau abandonneroit les parois du tuyau, & y laisseroit un vuide, si elle n'étoit pas comprimée par le poids de l'atmosphère."'' (It could therefore happen that the pressure in M might even become negative, and then the water would let go of the walls of the pipe, and would leave a void there, if it were not compressed by the weight of the atmosphere.)</ref> In 1859, the English mathematician [[W. H. Besant|William Henry Besant]] (1828–1917) published a solution to the problem of the dynamics of the collapse of a spherical cavity in a fluid, which had been presented by the Anglo-Irish mathematician [[Sir George Stokes, 1st Baronet|George Stokes]] (1819–1903) as one of the Cambridge [University] Senate-house problems and riders for the year 1847.<ref>{{cite book |last1=Besant |first1=W. H. |title=A Treatise on Hydrostatics and Hydrodynamics |date=1859 |publisher=Deighton, Bell, and Co. |location=Cambridge, England |pages=[https://archive.org/details/atreatiseonhydr01besagoog/page/n183 170]–171 |url=https://archive.org/details/atreatiseonhydr01besagoog}}</ref><ref>{{cite book |last1=(University of Cambridge) |title=The Examinations for the Degree of Bachelor of Arts, Cambridge, January 1847. |date=1847 |publisher=George Bell |location=London, England |page=13, problem 23 |chapter-url=https://books.google.com/books?id=kpxeAAAAcAAJ&pg=PA13 |chapter=The Senate-house Examination for Degrees in Honors, 1847.}}</ref>{{sfnp|Cravotto|Cintas|2012|p=26}} In 1894, Irish fluid dynamicist [[Osborne Reynolds]] (1842–1912) studied the formation and collapse of vapor bubbles in boiling liquids and in constricted tubes.<ref>See:
+As early as 1754, the Swiss mathematician [[Leonhard Euler]] (1707–1783) speculated about the possibility of cavitation.<ref>{{cite journal |last1=Euler |title=Théorie plus complete des machines qui sont mises en mouvement par la réaction de l'eau |journal=Mémoires de l'Académie Royale des Sciences et Belles-Lettres (Berlin) |date=1754 |volume=10 |pages=227–295 |language=fr |url=https://babel.hathitrust.org/cgi/pt?id=mdp.39015038659283;view=1up;seq=271 |trans-title=A more complete theory of machines that are set in motion by reaction against water}} See §LXXXI, pp. 266–267. From p. 266: ''"Il pourroit donc arriver que la pression en M devint même négative, & alors l'eau abandonneroit les parois du tuyau, & y laisseroit un vuide, si elle n'étoit pas comprimée par le poids de l'atmosphère."'' (It could therefore happen that the pressure in M might even become negative, and then the water would let go of the walls of the pipe, and would leave a void there, if it were not compressed by the weight of the atmosphere.)</ref> In 1859, the English mathematician [[W. H. Besant|William Henry Besant]] (1828–1917) published a solution to the problem of the dynamics of the collapse of a spherical cavity in a fluid, which had been presented by the Anglo-Irish mathematician [[Sir George Stokes, 1st Baronet|George Stokes]] (1819–1903) as one of the Cambridge University Senate-house problems and riders for the year 1847.<ref>{{cite book |last1=Besant |first1=W. H. |title=A Treatise on Hydrostatics and Hydrodynamics |date=1859 |publisher=Deighton, Bell, and Co. |location=Cambridge, England |pages=[https://archive.org/details/atreatiseonhydr01besagoog/page/n183 170]–171 |url=https://archive.org/details/atreatiseonhydr01besagoog}}</ref><ref>{{cite book |last1=(University of Cambridge) |title=The Examinations for the Degree of Bachelor of Arts, Cambridge, January 1847. |date=1847 |publisher=George Bell |location=London, England |page=13, problem 23 |chapter-url=https://books.google.com/books?id=kpxeAAAAcAAJ&pg=PA13 |chapter=The Senate-house Examination for Degrees in Honors, 1847.}}</ref>{{sfnp|Cravotto|Cintas|2012|p=26}} In 1894, Irish fluid dynamicist [[Osborne Reynolds]] (1842–1912) studied the formation and collapse of vapor bubbles in boiling liquids and in constricted tubes.<ref>See:
 *  {{cite journal |last1=Reynolds |first1=Osborne |title=Experiments showing the boiling of water in an open tube at ordinary temperatures |journal=Report of the Sixty-fourth Meeting of the British Association for the Advancement of Science Held at Oxford in August 1894 |date=1894 |volume=64 |page=564 |url=https://www.biodiversitylibrary.org/item/95243#page/688/mode/1up}}
 *  {{cite book |last1=Reynolds |first1=Osborne |title=Papers on Mechanical and Physical Subjects |date=1901 |publisher=Cambridge University Press |location=Cambridge, England |volume=2 |pages=578–587 |chapter-url=https://archive.org/details/papersonmechanic02reynrich/page/578 |chapter=Experiments showing the boiling of water in an open tube at ordinary temperatures}}</ref>
-The term ''cavitation'' first appeared in 1895 in a paper by [[John Isaac Thornycroft]] (1843–1928) and Sydney Walker Barnaby (1855–1925)—son of Sir [[Nathaniel Barnaby]] (1829 – 1915), who had been Chief Constructor of the Royal Navy—to whom it had been suggested by the British engineer Robert Edmund Froude (1846–1924), third son of the English hydrodynamicist [[William Froude]] (1810–1879).<ref>{{cite journal |last1=Thornycroft |first1=John Isaac |last2=Barnaby |first2=Sydney Walker |title=Torpedo-boat destroyers |journal=Minutes of the Proceedings of the Institution of Civil Engineers |date=1895 |volume=122 |issue=1895 |pages=51–69 |doi=10.1680/imotp.1895.19693 |url=https://babel.hathitrust.org/cgi/pt?id=hvd.hxgrq5;view=1up;seq=65}} From p. 67: " 'Cavitation,' as Mr. Froude has suggested to the Authors that the phenomenon should be called, … "</ref><ref>{{cite book |last1=Cravotto |first1=Giancarlo |last2=Cintas |first2=Pedro |editor1-last=Chen |editor1-first=Dong |editor2-last=Sharma |editor2-first=Sanjay K. |editor3-last=Mudhoo |editor3-first=Ackmez |title=Handbook on Applications of Ultrasound: Sonochemistry for Sustainability |date=2012 |publisher=CRC Press |location=Boca Raton, Florida, USA |page=27 |chapter-url=https://books.google.com/books?id=dSDOBQAAQBAJ&pg=PA27 |chapter=Chapter 2. Introduction to sonochemistry: A historical and conceptual overview|isbn=9781439842072 }}</ref>  Early experimental studies of cavitation were conducted in 1894–5 by Thornycroft and Barnaby and by the Anglo-Irish engineer [[Charles Algernon Parsons]] (1854–1931), who constructed a stroboscopic apparatus to study the phenomenon.<ref>{{cite journal |last1=Barnaby |first1=Sydney W. |title=On the formation of cavities in water by screw propellers at high speeds |journal=Transactions of the Royal Institution of Naval Architects |date=1897 |volume=39 |pages=139–144 |url=https://books.google.com/books?id=QtQ6AAAAMAAJ&pg=PA139}}</ref><ref>{{cite journal |last1=Parsons |first1=Charles |title=The application of the compound steam turbine to the purpose of marine propulsion |journal=Transactions of the Royal Institution of Naval Architects |date=1897 |volume=38 |pages=232–242 |url=https://books.google.com/books?id=Di85AQAAMAAJ&pg=PA232}} The stroboscope is described on p. 234:  "The screw [i.e., propeller] was illuminated by light from an arc lamp reflected from a revolving mirror attached to the screw shaft, which fell on it at one point only of the revolution, and by this means the shape, form, and growth of the cavities could be clearly seen and traced as if stationary."</ref><ref>See:
+The term ''cavitation'' first appeared in 1895 in a paper by [[John Isaac Thornycroft]] (1843–1928) and Sydney Walker Barnaby (1855–1925)—son of Sir [[Nathaniel Barnaby]] (1829 – 1915), who had been Chief Constructor of the Royal Navy—to whom it had been suggested by the British engineer Robert Edmund Froude (1846–1924), third son of the English hydrodynamicist [[William Froude]] (1810–1879).<ref>{{cite journal |last1=Thornycroft |first1=John Isaac |last2=Barnaby |first2=Sydney Walker |title=Torpedo-boat destroyers |journal=Minutes of the Proceedings of the Institution of Civil Engineers |date=1895 |volume=122 |issue=1895 |pages=51–69 |doi=10.1680/imotp.1895.19693 |url=https://babel.hathitrust.org/cgi/pt?id=hvd.hxgrq5;view=1up;seq=65}} From p. 67: " 'Cavitation,' as Mr. Froude has suggested to the Authors that the phenomenon should be called, … "</ref><ref>{{cite book |last1=Cravotto |first1=Giancarlo |last2=Cintas |first2=Pedro |editor1-last=Chen |editor1-first=Dong |editor2-last=Sharma |editor2-first=Sanjay K. |editor3-last=Mudhoo |editor3-first=Ackmez |title=Handbook on Applications of Ultrasound: Sonochemistry for Sustainability |date=2012 |publisher=CRC Press |location=Boca Raton, Florida, USA |page=27 |chapter-url=https://books.google.com/books?id=dSDOBQAAQBAJ&pg=PA27 |chapter=Chapter 2. Introduction to sonochemistry: A historical and conceptual overview|isbn=978-1-4398-4207-2 }}</ref>  Early experimental studies of cavitation were conducted in 1894–5 by Thornycroft and Barnaby and by the Anglo-Irish engineer [[Charles Algernon Parsons]] (1854–1931), who constructed a stroboscopic apparatus to study the phenomenon.<ref>{{cite journal |last1=Barnaby |first1=Sydney W. |title=On the formation of cavities in water by screw propellers at high speeds |journal=Transactions of the Royal Institution of Naval Architects |date=1897 |volume=39 |pages=139–144 |url=https://books.google.com/books?id=QtQ6AAAAMAAJ&pg=PA139}}</ref><ref>{{cite journal |last1=Parsons |first1=Charles |title=The application of the compound steam turbine to the purpose of marine propulsion |journal=Transactions of the Royal Institution of Naval Architects |date=1897 |volume=38 |pages=232–242 |url=https://books.google.com/books?id=Di85AQAAMAAJ&pg=PA232}} The stroboscope is described on p. 234:  "The screw [i.e., propeller] was illuminated by light from an arc lamp reflected from a revolving mirror attached to the screw shaft, which fell on it at one point only of the revolution, and by this means the shape, form, and growth of the cavities could be clearly seen and traced as if stationary."</ref><ref>See:
 * Parsons, Charles A. (1934) "Motive power — high-speed navigation steam turbines [address to the Royal Institution of Great Britain, delivered on 26 January 1900]". Parsons, G.L. (ed.). ''Scientific Papers and Addresses of the Hon. Sir Charles A. Parsons''. Cambridge England: Cambridge University Press. pp. 26–35.
 * {{cite journal |last1=Parsons |first1=Charles A. |title=Experimental apparatus shewing cavitation in screw propellers |journal=Transactions - North East Coast Institution of Engineers and Shipbuilders |date=1913 |volume=29 |pages=300–302 |url=https://babel.hathitrust.org/cgi/pt?id=mdp.39015039810455&view=1up&seq=434}}
@@ Line 204: / Line 204: @@
 *  {{cite journal |last1=Parsons |first1=Charles A. |last2=Cook |first2=Stanley S. |title=Investigations into the causes of corrosion or erosion of propellers |journal=Transactions of the Institution of Naval Architects |date=1919 |volume=61 |pages=223–247 |url=https://babel.hathitrust.org/cgi/pt?id=mdp.39015022701232;view=1up;seq=295}}
 *  {{cite journal |last1=Parsons |first1=Charles A. |last2=Cook |first2=Stanley S. |title=Investigations into the causes of corrosion or erosion of propellers |journal=Engineering |date=18 April 1919 |volume=107 |pages=515–519 |url=https://babel.hathitrust.org/cgi/pt?id=mdp.39015084594426;view=1up;seq=623}}
-*  {{cite journal |last1=Gibb |first1=Claude |title=Stanley Smith Cook. 1875-1952 |journal=Obituary Notices of Fellows of the Royal Society |date=November 1952 |volume=8 |issue=21 |pages=118–127|doi=10.1098/rsbm.1952.0008 |s2cid=119838312 }}; see pp. 123–124.</ref>  Experimental evidence of cavitation causing such high pressures was initially collected in 1952 by Mark Harrison (a fluid dynamicist and acoustician at the U.S. Navy's David Taylor Model Basin at Carderock, Maryland, USA) who used acoustic methods and in 1956 by Wernfried Güth (a physicist and acoustician of Göttigen University, Germany) who used optical [[Schlieren photography]].<ref>{{cite journal |last1=Harrison |first1=Mark |title=An experimental study of single bubble cavitation noise |journal=Journal of the Acoustical Society of America |date=1952 |volume=24 |issue=6 |pages=776–782|doi=10.1121/1.1906978 |bibcode=1952ASAJ...24..776H }}</ref><ref>{{cite journal |last1=Güth |first1=Wernfried |title=Entstehung der Stoßwellen bei der Kavitation |journal=Acustica |date=1956 |volume=6 |pages=526–531 |trans-title=Origin of shock waves during cavitation |language=de}}</ref><ref>{{cite book |last1=Krehl |first1=Peter O. K. |title=History of Shock Waves, Explosions and Impact: A Chronological and Biographical Reference |date=2009 |publisher=Springer Verlag |location=Berlin and Heidelberg, Germany |page=461 |url=https://books.google.com/books?id=PmuqCHDC3pwC&pg=PA461|isbn=9783540304210 }}</ref>
+*  {{cite journal |last1=Gibb |first1=Claude |title=Stanley Smith Cook. 1875-1952 |journal=Obituary Notices of Fellows of the Royal Society |date=November 1952 |volume=8 |issue=21 |pages=118–127|doi=10.1098/rsbm.1952.0008 |doi-access=free|s2cid=119838312 }}; see pp. 123–124.</ref>  Experimental evidence of cavitation causing such high pressures was initially collected in 1952 by Mark Harrison (a fluid dynamicist and acoustician at the U.S. Navy's David Taylor Model Basin at Carderock, Maryland, USA) who used acoustic methods and in 1956 by Wernfried Güth (a physicist and acoustician of Göttigen University, Germany) who used optical [[Schlieren photography]].<ref>{{cite journal |last1=Harrison |first1=Mark |title=An experimental study of single bubble cavitation noise |journal=Journal of the Acoustical Society of America |date=1952 |volume=24 |issue=6 |pages=776–782|doi=10.1121/1.1906978 |bibcode=1952ASAJ...24..776H }}</ref><ref>{{cite journal |last1=Güth |first1=Wernfried |title=Entstehung der Stoßwellen bei der Kavitation |journal=Acustica |date=1956 |volume=6 |pages=526–531 |trans-title=Origin of shock waves during cavitation |language=de}}</ref><ref>{{cite book |last1=Krehl |first1=Peter O. K. |title=History of Shock Waves, Explosions and Impact: A Chronological and Biographical Reference |date=2009 |publisher=Springer Verlag |location=Berlin and Heidelberg, Germany |page=461 |url=https://books.google.com/books?id=PmuqCHDC3pwC&pg=PA461|isbn=978-3-540-30421-0 }}</ref>
 [[File:Cavitation bubble implosion.png|right|frame|The implosion of a cavitation bubble causes a high-speed jet of fluid to impact a fixed surface]]
-In 1944, Soviet scientists Mark Iosifovich Kornfeld (1908–1993) and L. Suvorov of the Leningrad Physico-Technical Institute (now:  the Ioffe Physical-Technical Institute of the Russian Academy of Sciences, St. Petersburg, Russia) proposed that during cavitation, bubbles in the vicinity of a solid surface do not collapse symmetrically; instead, a dimple forms on the bubble at a point opposite the solid surface and this dimple evolves into a jet of liquid.  This jet of liquid damages the solid surface.<ref>{{cite journal |last1=Kornfeld |first1=M. |last2=Suvorov |first2=L. |title=On the destructive action of cavitation |journal=Journal of Applied Physics |date=1944 |volume=15 |issue=6 |pages=495–506|doi=10.1063/1.1707461 |bibcode=1944JAP....15..495K }}</ref>  This hypothesis was supported in 1951 by theoretical studies by Maurice Rattray Jr., a doctoral student at the [[California Institute of Technology]].<ref>Rattray, Maurice, Jr. (1951) [https://thesis.library.caltech.edu/1493/1/Rattray_m_1951.pdf ''Perturbation effects in cavitation bubble dynamics.'']  Ph.D. thesis, California Institute of Technology (Pasadena, California, USA).</ref>  Kornfeld and Suvorov's hypothesis was confirmed experimentally in 1961 by Charles F. Naudé and Albert T. Ellis, fluid dynamicists at the California Institute of Technology.<ref>{{cite journal |last1=Naudé |first1=Charles F. |last2=Ellis |first2=Albert T. |title=On the mechanism of cavitation damage by nonhemispherical cavities in contact with a solid boundary |journal=Journal of Basic Engineering |date=1961 |volume=83 |issue=4 |pages=648–656 |doi=10.1115/1.3662286 |s2cid=11867895 |url=https://authors.library.caltech.edu/48933/1/On%20the%20Mechanism%20of%20Cavitation%20Damage%20by%20Nonhemispherical%20Cavities%20Collapsing%20in%20Contact%20With%20a%20Solid%20Boundary.pdf |archive-url=https://web.archive.org/web/20180724061708/https://authors.library.caltech.edu/48933/1/On%20the%20Mechanism%20of%20Cavitation%20Damage%20by%20Nonhemispherical%20Cavities%20Collapsing%20in%20Contact%20With%20a%20Solid%20Boundary.pdf |archive-date=2018-07-24 |url-status=live }}  Available at:
+In 1944, Soviet scientists Mark Iosifovich Kornfeld (1908–1993) and L. Suvorov of the Leningrad Physico-Technical Institute (now:  the Ioffe Physical-Technical Institute of the Russian Academy of Sciences, St. Petersburg, Russia) proposed that during cavitation, bubbles in the vicinity of a solid surface do not collapse symmetrically; instead, a dimple forms on the bubble at a point opposite the solid surface and this dimple evolves into a jet of liquid.  This jet of liquid damages the solid surface.<ref>{{cite journal |last1=Kornfeld |first1=M. |last2=Suvorov |first2=L. |title=On the destructive action of cavitation |url=https://archive.org/details/sim_journal-of-applied-physics_1944-06_15_6/page/494 |journal=Journal of Applied Physics |date=1944 |volume=15 |issue=6 |pages=495–506|doi=10.1063/1.1707461 |bibcode=1944JAP....15..495K }}</ref>  This hypothesis was supported in 1951 by theoretical studies by Maurice Rattray Jr., a doctoral student at the [[California Institute of Technology]].<ref>Rattray, Maurice, Jr. (1951) [https://thesis.library.caltech.edu/1493/1/Rattray_m_1951.pdf ''Perturbation effects in cavitation bubble dynamics.''] {{Webarchive|url=https://web.archive.org/web/20161022205009/http://thesis.library.caltech.edu/1493/1/Rattray_m_1951.pdf |date=2016-10-22  }}  Ph.D. thesis, California Institute of Technology (Pasadena, California, USA).</ref>  Kornfeld and Suvorov's hypothesis was confirmed experimentally in 1961 by Charles F. Naudé and Albert T. Ellis, fluid dynamicists at the California Institute of Technology.<ref>{{cite journal |last1=Naudé |first1=Charles F. |last2=Ellis |first2=Albert T. |title=On the mechanism of cavitation damage by nonhemispherical cavities in contact with a solid boundary |journal=Journal of Basic Engineering |date=1961 |volume=83 |issue=4 |pages=648–656 |doi=10.1115/1.3662286 |s2cid=11867895 |url=https://authors.library.caltech.edu/48933/1/On%20the%20Mechanism%20of%20Cavitation%20Damage%20by%20Nonhemispherical%20Cavities%20Collapsing%20in%20Contact%20With%20a%20Solid%20Boundary.pdf |archive-url=https://web.archive.org/web/20180724061708/https://authors.library.caltech.edu/48933/1/On%20the%20Mechanism%20of%20Cavitation%20Damage%20by%20Nonhemispherical%20Cavities%20Collapsing%20in%20Contact%20With%20a%20Solid%20Boundary.pdf |archive-date=2018-07-24 |url-status=live }}  Available at:
   [https://authors.library.caltech.edu/48933/1/On%20the%20Mechanism%20of%20Cavitation%20Damage%20by%20Nonhemispherical%20Cavities%20in%20Contact%20with%20a%20Solid%20Boundary.pdf California Institute of Technology (Pasadena, California, USA).]{{Dead link|date=July 2020 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>
-A series of experimental investigations of the propagation of strong [[shock wave]] (SW) in a liquid with gas bubbles, which made it possible to establish the basic laws governing the process, the mechanism for the transformation of the energy of the SW, attenuation of the SW, and the formation of the structure, and experiments on the analysis of the attenuation of waves in bubble screens with different acoustic properties were begun by pioneer works of Soviet scientist prof.[[Vladilen F. Minin|V.F. Minin]] at the Institute of Hydrodynamics (Novosibirsk, Russia) in 1957–1960, who examined also the first convenient model of a screen - a sequence of alternating flat one-dimensional liquid and gas layers.<ref name="minin">{{cite journal| last1=Shipilov| first1=S.E.| last2=Yakubov| first2=V.P.| title=History of technical protection. 60 years in science: to the jubilee of Prof. V.F. Minin| journal=IOP Conf. Series: Materials Science and Engineering| publisher=[[IOP Publishing]]| volume=363| issue=12033| date=2018| page=012033| doi=10.1088/1757-899X/363/1/012033| bibcode=2018MS&E..363a2033S| doi-access=free}}</ref> In an experimental investigations of the dynamics of the form of pulsating gaseous cavities and interaction of SW with bubble clouds in 1957–1960 [[Vladilen F. Minin|V.F. Minin]] discovered that under the action of SW a bubble collapses asymmetrically with the formation of a cumulative jet, which forms in the process of collapse and causes fragmentation of the bubble.<ref name="minin" />
+A series of experimental investigations of the propagation of strong [[shock wave]] (SW) in a liquid with gas bubbles, which made it possible to establish the basic laws governing the process, the mechanism for the transformation of the energy of the SW, attenuation of the SW, and the formation of the structure, and experiments on the analysis of the attenuation of waves in bubble screens with different acoustic properties were begun by pioneer works of Soviet scientist prof.[[Vladilen F. Minin|V.F. Minin]] at the Institute of Hydrodynamics (Novosibirsk, Russia) in 1957–1960, who examined also the first convenient model of a screen - a sequence of alternating flat one-dimensional liquid and gas layers.<ref name="minin">{{cite journal| last1=Shipilov| first1=S.E.| last2=Yakubov| first2=V.P.| title=History of technical protection. 60 years in science: to the jubilee of Prof. V.F. Minin| journal=IOP Conf. Series: Materials Science and Engineering| publisher=[[IOP Publishing]]| volume=363| issue=12033| date=2018| article-number=012033| doi=10.1088/1757-899X/363/1/012033| bibcode=2018MS&E..363a2033S| doi-access=free}}</ref> In an experimental investigations of the dynamics of the form of pulsating gaseous cavities and interaction of SW with bubble clouds in 1957–1960 [[Vladilen F. Minin|V.F. Minin]] discovered that under the action of SW a bubble collapses asymmetrically with the formation of a cumulative jet, which forms in the process of collapse and causes fragmentation of the bubble.<ref name="minin" />
 ==See also==
@@ Line 217: / Line 217: @@
 * {{annotated link|Cavitation modelling}}
 * {{annotated link|Erosion corrosion of copper water tubes}}
-* {{annotated link|Rayleigh-Plesset equation}}
+* {{annotated link|Rayleigh–Plesset equation}}
 * {{annotated link|Sonoluminescence}}
 * {{annotated link|Supercavitation}}
@@ Line 231: / Line 231: @@
 * For cavitation in plants, see ''Plant Physiology'' by Taiz and Zeiger.
 * For cavitation in the engineering field, visit [http://www.corrosion-doctors.org/Forms-cavitation/cavitation.htm Cavitation corrosion] {{Webarchive|url=https://web.archive.org/web/20070624004920/http://www.corrosion-doctors.org/Forms-cavitation/cavitation.htm |date=2007-06-24  }}
-* {{cite journal | last1 = Kornfelt | first1 = M. | year = 1944 | title = On the destructive action of cavitation | journal = Journal of Applied Physics | volume = 15 | issue = 6| pages = 495–506 | bibcode = 1944JAP....15..495K | doi = 10.1063/1.1707461 }}
+* {{cite journal | last1 = Kornfelt | first1 = M. | year = 1944 | title = On the destructive action of cavitation | url = https://archive.org/details/sim_journal-of-applied-physics_1944-06_15_6/page/494 | journal = Journal of Applied Physics | volume = 15 | issue = 6| pages = 495–506 | bibcode = 1944JAP....15..495K | doi = 10.1063/1.1707461 }}
 * For hydrodynamic cavitation in the ethanol field, visit [http://www.arisdyne.com/ Arisdyne] {{Webarchive|url=https://web.archive.org/web/20130710201353/http://www.arisdyne.com/ |date=2013-07-10  }} and Ethanol Producer Magazine: "Tiny Bubbles to Make You Happy" [http://www.ethanolproducer.com/article.jsp?article_id=5732&q=tiny%20bubbles&category_id=46]{{Dead link|date=August 2023 |bot=InternetArchiveBot |fix-attempted=yes }}
 * {{cite journal | last1 = Barnett | first1 = S. | year = 1998 | title = Nonthermal issues: Cavitation—Its nature, detection and measurement; | journal = Ultrasound in Medicine & Biology | volume = 24 | pages = S11–S21 | doi=10.1016/s0301-5629(98)00074-x}}
@@ Line 239: / Line 239: @@
 {{Wiktionary|cavitation}}
 {{commons category|Cavitation}}
-* [http://cav.safl.umn.edu/ Cavitation and Bubbly Flows, Saint Anthony Falls Laboratory, University of Minnesota]
+* [https://cav.safl.umn.edu/ Cavitation and Bubbly Flows, Saint Anthony Falls Laboratory, University of Minnesota]
 * [https://web.archive.org/web/20060206151508/http://caltechbook.library.caltech.edu/1/04/bubble.htm Cavitation and Bubble Dynamics by Christopher E. Brennen]
 * [https://web.archive.org/web/20060324065024/http://caltechbook.library.caltech.edu/51/01/multiph.htm Fundamentals of Multiphase Flow by Christopher E. Brennen]

Cavitation: Difference between revisions

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