Cavitation and bubble dynamics: the Kelvin impulse and its applications

Cavitation and bubble dynamics have a wide range of practical applications in a range of disciplines, including hydraulic, mechanical and naval engineering, oil exploration, clinical medicine and sonochemistry. However, this paper focuses on how a fundamental concept, the Kelvin impulse, can provide practical insights into engineering and industrial design problems. The pathway is provided through physical insight, idealized experiments and enhancing the accuracy and interpretation of the computation. In 1966, Benjamin and Ellis made a number of important statements relating to the use of the Kelvin impulse in cavitation and bubble dynamics, one of these being ‘One should always reason in terms of the Kelvin impulse, not in terms of the fluid momentum…’. We revisit part of this paper, developing the Kelvin impulse from first principles, using it, not only as a check on advanced computations (for which it was first used!), but also to provide greater physical insights into cavitation bubble dynamics near boundaries (rigid, potential free surface, two-fluid interface, flexible surface and axisymmetric stagnation point flow) and to provide predictions on different types of bubble collapse behaviour, later compared against experiments. The paper concludes with two recent studies involving (i) the direction of the jet formation in a cavitation bubble close to a rigid boundary in the presence of high-intensity ultrasound propagated parallel to the surface and (ii) the study of a ‘paradigm bubble model’ for the collapse of a translating spherical bubble, sometimes leading to a constant velocity high-speed jet, known as the Longuet-Higgins jet.

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Cavitation bubble dynamics in a liquid gap of variable height

Journal of Fluid Mechanics ◽

10.1017/jfm.2011.212 ◽

2011 ◽

Vol 682 ◽

pp. 241-260 ◽

Cited By ~ 42

Author(s):

SILVESTRE ROBERTO GONZALEZ-AVILA ◽

EVERT KLASEBOER ◽

BOO CHEONG KHOO ◽

CLAUS-DIETER OHL

Keyword(s):

Cavitation Bubble ◽

High Speed ◽

Strong Influence ◽

Bubble Dynamics ◽

Bubble Collapse ◽

High Speed Photography ◽

Expansion Time ◽

Gap Height ◽

Bubble Splitting ◽

Narrow Gaps

We report on an experimental study of cavitation bubble dynamics within sub-millimetre-sized narrow gaps. The gap height is varied, while the position of the cavitation event is fixed with respect to the lower gap wall. Four different sizes of laser-induced cavitation bubbles are studied using high-speed photography of up to 430,000 frames per second. We find a strong influence of the gap height, H, on the bubble dynamics, in particular on the collapse scenario. Also, similar bubble dynamics was found for the same non-dimensional gap height η = H/Rx, where Rx is the maximum radius in the horizontal direction. Three scenarios are observed: neutral collapse at the gap centre, collapse onto the lower wall and collapse onto the upper wall. For intermediate gap height the bubble obtains a conical shape 1.4 < η < 7.0. For large distances, η > 7.0, the bubble no longer feels the presence of the upper wall and collapses hemispherically. The collapse time increases with respect to the expansion time for decreasing values of η. Due to the small scales involved, the final stage of the bubble collapse could not be resolved temporally and numerical simulations were performed to elucidate the details of the flow. The simulations demonstrate high-speed jetting towards the upper and lower walls and complex bubble splitting for neutral collapses.

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Fast transient microjets induced by hemispherical cavitation bubbles

Journal of Fluid Mechanics ◽

10.1017/jfm.2015.33 ◽

2015 ◽

Vol 767 ◽

pp. 31-51 ◽

Cited By ~ 28

Author(s):

Silvestre Roberto Gonzalez Avila ◽

Chaolong Song ◽

Claus-Dieter Ohl

Keyword(s):

Cavitation Bubble ◽

High Speed ◽

Bubble Dynamics ◽

Silicone Oil ◽

Bubble Collapse ◽

High Speed Photography ◽

Drug Delivery Device ◽

Spray Formation ◽

Novel Method ◽

Fast Transient

AbstractWe report on a novel method to generate fast transient microjets and study their characteristics. The simple device consists of two electrodes on a substrate with a hole in between. The side of the substrate with the electrodes is submerged in a liquid. Two separate microjets exit through the tapered hole after an electrical discharge is induced between the electrodes. They are formed during the expansion and collapse of a single cavitation bubble. The cavitation bubble dynamics as well as the jets were studied with high-speed photography at up to 500 000 f.p.s. With increasing jet velocity they become unstable and spray formation is observed. The jet created during expansion (first jet) is in most cases slower than the jet created during bubble collapse, which can reach up to $400~\text{m}~\text{s}^{-1}$. The spray exiting the orifice is at least in part due to the presence of cavitation in the microchannel as observed by high-speed recording. The effect of viscosity was tested using silicone oil of 10, 50 and 100 cSt. Interestingly, for all liquids the transition from a stable to an unstable jet occurs at $We\sim 4600$. We demonstrate that these microjets can penetrate into soft material; thus they can be potentially used as a needleless drug delivery device.

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The Boundary Integral Method Applied to Non-Spherical Cavitation Bubble Growth and Collapse Close to a Rigid Boundary

Volume 8A: Heat Transfer and Thermal Engineering ◽

10.1115/imece2015-51687 ◽

2015 ◽

Author(s):

Ali Alhelfi ◽

Bengt Sunden

Keyword(s):

Cavitation Bubble ◽

Integral Method ◽

Bubble Dynamics ◽

Boundary Integral ◽

Solid Surfaces ◽

Boundary Integral Method ◽

Bubble Collapse ◽

Surface Erosion ◽

Rigid Boundary ◽

Cavitation Phenomenon

Recently much attention has been paid to studies concerning bubble dynamics in the cavitation phenomena and this topic has been the subject of many research works. In fact, the simulation of non-spherical bubble dynamics and its interaction with solid boundaries have received much less attention due to the complexity of the problem. One of the main reasons of the structural damages in the cavitation phenomenon is due to the formation of micro jets generated due to the bubble collapse and impinging on the solid surfaces or boundaries. The boundary integral method (BIM) based on Green’s function is used to model the oscillation and collapse of a cavitation bubble close to a rigid boundary. The liquid is considered to be incompressible, inviscid, and irrational around the bubble. These assumptions satisfy the conditions for the Laplacian equation. The theory permits one to predict correctly the interaction between the bubble and the rigid boundary, which is of great importance in the study of cavitation damage due to a bubble collapsing close to the boundaries. The results reveal that the amplitude of bubble oscillation depends on the bubble location away from a rigid surface. Also, the theory for the cavitation bubble dynamics presented in this study has many advantages in various situations and might be helpful to understand effects of the cavitation phenomenon such as generation of excessive vibration, surface erosion and undesirable acoustic emission.

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Study of cavitation bubble dynamics during Ho:YAG laser lithotripsy by high-speed camera

10.1117/12.2207487 ◽

2016 ◽

Cited By ~ 1

Author(s):

Jian J. Zhang ◽

Jason R. Xuan ◽

Honggang Yu ◽

Dennis Devincentis

Keyword(s):

Cavitation Bubble ◽

High Speed ◽

Bubble Dynamics ◽

Laser Lithotripsy ◽

High Speed Camera ◽

Ho:Yag Laser

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Cavitation erosion behavior of hydraulic concrete under high-speed flow

Anti-Corrosion Methods and Materials ◽

10.1108/acmm-03-2021-2459 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Xin Wang ◽

Ting-Qiang Xie

Keyword(s):

Cavitation Bubble ◽

High Speed ◽

Cavitation Erosion ◽

Concrete Strength ◽

Bubble Collapse ◽

High Speed Flow ◽

Content Type ◽

Erosion Behavior ◽

Hydraulic Concrete ◽

Speed Flow

Purpose Cavitation erosion has always been a common technical problem in a hydraulic discharging structure. This paper aims to investigate the cavitation erosion behavior of hydraulic concrete under high-speed flow. Design/methodology/approach A high-speed and high-pressure venturi cavitation erosion generator was used to simulate the strong cavitation. The characteristics of hydrodynamic loads of cavitation bubble collapse zone, the failure characteristics and the erosion development process of concrete were investigated. The main influencing factors of cavitation erosion were discussed. Findings The collapse of the cavitation bubble group produced a high frequency, continuous and unsteady pulse load on the wall of concrete, which was more likely to cause fatigue failure of concrete materials. The cavitation action position and the main frequency of impact load were greatly affected by the downstream pressure. A power exponential relationship between cavitation load, cavitation erosion and flow speed was observed. With the increase of concrete strength, the degree of damage of cavitation erosion was approximately linearly reduced. Originality/value After cavitation erosion, a skeleton structure was formed by the accumulation of granular particles, and the relatively independent bulk structure of the surface differed from the flake structure formed after abrasion.

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A Photographic Study of Spark-Induced Cavitation Bubble Collapse

Journal of Basic Engineering ◽

10.1115/1.3425571 ◽

1972 ◽

Vol 94 (4) ◽

pp. 825-832 ◽

Cited By ~ 66

Author(s):

C. L. Kling ◽

F. G. Hammitt

Keyword(s):

Cavitation Bubble ◽

High Speed ◽

Bubble Collapse ◽

Solid Boundary ◽

High Speed Photography ◽

Minimum Volume ◽

Cavitation Bubbles ◽

Flowing System

The collapse of spark-induced cavitation bubbles in a flowing system was studied by means of high speed photography. The migration of cavitation bubbles toward a nearby solid boundary during collapse and rebound was observed. Near its minimum volume the bubble typically formed a high speed microjet, which struck the nearby surface causing individual damage craters on soft aluminum.

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Directional soliton and breather beams

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1821970116 ◽

2019 ◽

Vol 116 (20) ◽

pp. 9759-9763 ◽

Cited By ~ 4

Author(s):

Amin Chabchoub ◽

Kento Mozumi ◽

Norbert Hoffmann ◽

Alexander V. Babanin ◽

Alessandro Toffoli ◽

...

Keyword(s):

High Speed ◽

Evolution Equations ◽

Rogue Waves ◽

Fundamental Solutions ◽

Dispersive Media ◽

Unstable Wave ◽

Practical Applications ◽

Wide Range ◽

Plasma Hydrodynamics ◽

Crest Length

Solitons and breathers are nonlinear modes that exist in a wide range of physical systems. They are fundamental solutions of a number of nonlinear wave evolution equations, including the unidirectional nonlinear Schrödinger equation (NLSE). We report the observation of slanted solitons and breathers propagating at an angle with respect to the direction of propagation of the wave field. As the coherence is diagonal, the scale in the crest direction becomes finite; consequently, beam dynamics form. Spatiotemporal measurements of the water surface elevation are obtained by stereo-reconstructing the positions of the floating markers placed on a regular lattice and recorded with two synchronized high-speed cameras. Experimental results, based on the predictions obtained from the (2D + 1) hyperbolic NLSE equation, are in excellent agreement with the theory. Our study proves the existence of such unique and coherent wave packets and has serious implications for practical applications in optical sciences and physical oceanography. Moreover, unstable wave fields in this geometry may explain the formation of directional large-amplitude rogue waves with a finite crest length within a wide range of nonlinear dispersive media, such as Bose–Einstein condensates, solids, plasma, hydrodynamics, and optics.

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Investigation on cavitation bubble dynamics induced by clinically available Ho:YAG lasers

Photonics and Lasers in Medicine ◽

10.1515/plm-2015-0039 ◽

2016 ◽

Vol 5 (2) ◽

Cited By ~ 1

Author(s):

Karl Stock ◽

Daniel Steigenhöfer ◽

Thomas Pongratz ◽

Rainer Graser ◽

Ronald Sroka

Keyword(s):

Cavitation Bubble ◽

Bubble Dynamics ◽

Laser Energy ◽

Bubble Collapse ◽

High Contrast ◽

Core Diameter ◽

Ho:Yag Laser ◽

Fiber Core ◽

Set Up ◽

Short Time

AbstractEndoscopic laser lithotripsy is the preferred technique for minimally invasive destruction of ureteral and kidney stones, and is mostly performed by pulsed holmium:yttrium-aluminum-garnet (Ho:YAG) laser irradiation. The absorbed laser energy heats the water creating a vapor bubble which collapses after the laser pulse, thus producing a shock wave. Part of the laser energy strikes the stone through the vapor bubble and induces thermomechanical material removal. Aim of the present study was to visualize the behavior and the dynamics of the cavitation bubble using a specially developed ultra-short-time illumination system and then to determine important characteristics related to clinically used laser and application parameters for a more detailed investigation in the future.In accordance with Toepler’s Schlieren technique, in the ultra-short-time-illumination set-up the cavitation bubble which had been induced by Ho:YAG laser irradiation at the fiber end, was illuminated by two Q-switched lasers and the process was imaged in high contrast on a video camera. Cavitation bubbles were induced using different pulse energies (500 mJ/pulse and 2000 mJ/pulse) and fiber core diameters (230 μm and 600 μm) and the bubble dynamics were recorded at different times relative to the Ho:YAG laser pulse. The time-dependent development of the bubble formation was determined from the recordings by measuring the bubble diameter in horizontal and vertical directions, together with the volume and localization of the center of the bubble collapse.The results show that the bubble dynamics can be visualized and studied with both high contrast and high temporal resolution. The bubble volume increases with pulse energy and with fiber diameter. The bubble shape is almost round when a larger fiber core diameter is used, and elliptical when using a fiber of smaller core diameter. Moreover, the center of the resulting bubble is slightly further away from the fiber end and the center of the bubble collapse for a smaller fiber core diameter.The experimental set-up developed gives a better understanding of the bubble dynamics. The experiments indicate that the distance between fiber tip and target surface, as well as the laser parameters used have considerable impact on the cavitation bubble dynamics. Both the bubble dynamics and their influence on the stone fragmentation process require further investigation.

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