Pulsed jets driven by two interacting cavitation bubbles produced at different times

2017 ◽  
Vol 819 ◽  
pp. 465-493 ◽  
Author(s):  
Y. Tomita ◽  
K. Sato
Keyword(s):  
High Speed ◽  
Time Difference ◽  
Interaction Parameters ◽  
Bubble Collapse ◽  
High Speed Photography ◽  
Bubble Generation ◽  
Spray Formation ◽  
Cavitation Bubbles ◽  
Toroidal Bubble ◽  
Jet Impact

An experiment is performed using high-speed photography to elucidate the behaviours of jets formed by the interactions of two laser-induced tandem bubbles produced axisymmetrically for a range of dimensionless interaction parameters such as the bubble size ratio, $\unicode[STIX]{x1D709}$, the distance between the two cavitation bubbles, $l_{0}^{\ast }$, and the time difference in bubble generation, $\unicode[STIX]{x0394}\unicode[STIX]{x1D703}^{\ast }$. A strong interaction occurs for $l_{0}^{\ast }<1$. The first bubble produced (bubble A) deforms because of the rapid growth of the second bubble (bubble B) to create a pulsed conical jet, sometimes with spray formation at the tip, formed by the small amount of water confined between the two bubbles. This phenomenon is followed by bubble penetration, toroidal bubble collapse, and the subsequent fast contraction of bubble B accompanied by a fine jet. The formation mechanism of the conical jet is similar to that of a water spike developed in air from a deformed free surface of a single growing bubble; however, the pressures of the gases surrounding each type of jet differ. The jet behaviours can be controlled by manipulating the interaction parameters; the jet velocity is significantly affected by $\unicode[STIX]{x1D709}$ and $l_{0}^{\ast }$, but less so by $\unicode[STIX]{x0394}\unicode[STIX]{x1D703}^{\ast }$ for $\unicode[STIX]{x0394}\unicode[STIX]{x1D703}^{\ast }>\unicode[STIX]{x0394}\unicode[STIX]{x1D703}_{c}^{\ast }$ ($\unicode[STIX]{x0394}\unicode[STIX]{x1D703}_{c}^{\ast }$ being the critical birth-time difference). The optimum time of jet impact, at which bubble A reaches its maximum volume, depends on $\unicode[STIX]{x0394}\unicode[STIX]{x1D703}^{\ast }$. It is generally later for larger values of $\unicode[STIX]{x1D709}$. A pulsed jet could be used to create small pores in a cell membrane; therefore, the reported method may be useful for application in tandem-bubble sonoporation.

scholarly journals A Photographic Study of Spark-Induced Cavitation Bubble Collapse

1972 ◽  
Vol 94 (4) ◽  
pp. 825-832 ◽  
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.

Dynamics of laser-induced cavitation bubbles near two perpendicular rigid walls

2018 ◽  
Vol 841 ◽  
pp. 28-49 ◽  
Author(s):  
Emil-Alexandru Brujan ◽  
Tatsuya Noda ◽  
Atsushi Ishigami ◽  
Toshiyuki Ogasawara ◽  
Hiroyuki Takahira
Keyword(s):  
High Speed ◽  
Vertical Wall ◽  
Bubble Surface ◽  
Bubble Collapse ◽  
High Speed Photography ◽  
Maximum Expansion ◽  
Toroidal Bubble ◽  
Horizontal Wall ◽  
The Moment ◽  
Rigid Walls

The behaviour of a laser-induced cavitation bubble near two perpendicular rigid walls and its dependence on the distance between bubble and walls is investigated experimentally. It was shown by means of high-speed photography with $100\,000~\text{frames}~\text{s}^{-1}$ that an inclined jet is formed during bubble collapse and the bubble migrates in the direction of the jet. At a given position of the bubble with respect to the horizontal wall, the inclination of the jet increases with decreasing distance between the bubble and the second, vertical wall. A bubble generated at equal distances from the walls develops a jet that is directed in their bisection. The penetration of the jet into the opposite bubble surface leads to the formation of an asymmetric toroidal bubble that is perpendicular to the jet direction. At a large distance from the rigid walls, the toroidal bubble collapses in the radial direction, eventually disintegrating into tiny microbubbles. When the bubble is in contact with the horizontal wall at its maximum expansion, the toroidal ring collapses in both radial and toroidal directions, starting from the bubble part opposite to the vertical wall, and the bubble achieves a crescent shape at the moment of second collapse. The bubble oscillation is accompanied by a strong migration along the horizontal wall.

Growth and collapse of cavitation bubbles near a curved rigid boundary

2002 ◽  
Vol 466 ◽  
pp. 259-283 ◽  
Author(s):  
Y. TOMITA ◽  
P. B. ROBINSON ◽  
R. P. TONG ◽  
J. R. BLAKE
Keyword(s):  
Boundary Integral ◽  
Bubble Collapse ◽  
Liquid Jet ◽  
High Speed Photography ◽  
Bubble Motion ◽  
Mean Flow ◽  
Rigid Boundary ◽  
Convex Boundary ◽  
Cavitation Bubbles ◽  
Toroidal Bubble

Laser-induced cavitation bubbles near a curved rigid boundary are observed experimentally using high-speed photography. An image theory is applied to obtain information on global bubble motion while a boundary integral method is employed to gain a more detailed understanding of the behaviour of a liquid jet that threads a collapsing bubble, creating a toroidal bubble. Comparisons between the theory and experiment show that when a comparable sized bubble is located near a rigid boundary the bubble motion is significantly influenced by the surface curvature of the boundary, which is characterized by a parameter ζ, giving convex walls for ζ < 1, concave walls for ζ > 1 and a flat wall when ζ = 1. If a boundary is slightly concave, the most pronounced migration occurs at the first bubble collapse. The velocity of a liquid jet impacting on the far side of the bubble surface tends to increase with decreasing parameter ζ. In the case of a convex boundary, the jet velocity is larger than that generated in the flat boundary case. Although the situation considered here is restricted to axisymmetric motion without mean flow, this result suggests that higher pressures can occur when cavitation bubbles collapse near a non-flat boundary. Bubble separation, including the pinch-off phenomenon, is observed in the final stage of the collapse of a bubble, with the oblate shape at its maximum volume attached to the surface of a convex boundary, followed by bubble splitting which is responsible for further bubble proliferation.

scholarly journals Fast transient microjets induced by hemispherical cavitation bubbles

2015 ◽  
Vol 767 ◽  
pp. 31-51 ◽  
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.

scholarly journals High-speed jetting and spray formation from bubble collapse

2012 ◽  
Vol 85 (1) ◽  
Author(s):  
Badarinath Karri ◽  
Silvestre Roberto Gonzalez Avila ◽  
Yee Chong Loke ◽  
Sean J. O’Shea ◽  
Evert Klaseboer ◽  
...  
Keyword(s):  
High Speed ◽  
Bubble Collapse ◽  
Spray Formation

Structure of Emulsion Cavitation Jet and Jet Peening Impact on the Fatigue of Plan Carbon Steel Q235A

2011 ◽  
Vol 189-193 ◽  
pp. 476-483
Author(s):  
Zhi Sun ◽  
Yan Wei Sui ◽  
Jun Li ◽  
Yan Ni Zhou
Keyword(s):  
Carbon Steel ◽  
High Speed ◽  
Test System ◽  
Water Jet ◽  
High Speed Photography ◽  
Strengthening Effect ◽  
Initial Stage ◽  
Jet Impact ◽  
Upstream Pressure ◽  
Crack Initiation Life

Due to developing the strengthening effect of liquid jet peening on the surface modification for metallic materials, in this study, an emulsion jet peening is produced by injecting a high-speed emulsion jet into an emulsion filled tank. The test system and fixed emulsion of cavitation jet was developed. High speed photography technique was used to observe and analysis the structure of emulsion cavitation jet at various upstream pressures . The results indicate that the structure of emulsion cavitation jet in terms of jet impact pressure, intensive degree and uniformity is better than that water jet. The jet structure depends on the jet pressure. The cavitation jet length increases rapidly at the initial stage and then it stabilizes after few milliseconds. The stabilized length of jet increases and the diverges angle decreases with increasing pressures. Specimens made of plan carbon steel (Q235A, China standard) were exposed to emulsion jet peening at the stand-off distances of 20 mm with a constant upstream pressure, 20 MPa for 60 s. The fatigue test shows that the crack initiation life by treatment of emulsion jet peening increases about 12.5% and 20.2% compared to water jet and unpeened specimen respectively.

scholarly journals Simulation of the Collapse of an Underwater Explosion Bubble under a Circular Plate

2005 ◽  
Vol 12 (3) ◽  
pp. 217-225 ◽  
Author(s):  
Kit-Keung Kan ◽  
James H. Stuhmiller ◽  
Philemon C. Chan
Keyword(s):  
Hydraulic Jump ◽  
Underwater Explosion ◽  
Complex Interaction ◽  
Bubble Collapse ◽  
Toroidal Bubble ◽  
Jet Impact ◽  
Advection Term ◽  
Two Fluid ◽  
Insight Into ◽  
Good Agreement

A two-fluid, computational fluid dynamics study of the phenomena of bubble collapse under a submersed flat plate has been performed. In order to handle the rapidly changing bubble-water interface accurately, second order upwind differencing is used in calculating the advection term. Good agreement with experimental data is obtained for the pressure distribution on the plate. The computational results provide insight into the phenomenology of the jet impact, the formation of a radial hydraulic jump, and the complex interaction of that hydraulic jump with the collapsing toroidal bubble.

scholarly journals Dynamic Characteristics of Bubble Collapse Near the Liquid-Liquid Interface

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2794
Author(s):  
Zhaoqin Yin ◽  
Zemin Huang ◽  
Chengxu Tu ◽  
Xiaoyan Gao ◽  
Fubing Bao
Keyword(s):  
Dynamic Characteristics ◽  
High Speed ◽  
Liquid Droplet ◽  
Liquid Interface ◽  
Bubble Collapse ◽  
Dynamic Evolution ◽  
Liquid Jet ◽  
Bubble Generation ◽  
Generation Expansion ◽  
Different Shapes

Bubble collapse near the liquid-liquid interface was experimentally studied in this paper, and the dynamic evolution of a laser-induced bubble (generation, expansion, and collapse) and the liquid-liquid interface (dent and rebound) were captured by a high-speed shadowgraph system. The effect of the dimensionless distance between the bubble and the interface on the direction of the liquid jet, the direction of bubble migration, and the dynamics of bubble collapse were discussed. The results show that: (1) The jet generated during bubble collapse always directs toward the denser fluid; (2) bubble collapses penetrate the interface when the bubble is close to the interface; (3) three different shapes of the liquid-liquid interface—that is, a mushroom-shaped liquid column, a spike droplet, and a spherical liquid droplet—were observed.

Effect of Nozzle Shape and Polymer Additives on Water Jet Appearance

1979 ◽  
Vol 101 (3) ◽  
pp. 304-308 ◽  
Author(s):  
J. W. Hoyt ◽  
J. J. Taylor
Keyword(s):  
Boundary Layer ◽  
High Speed ◽  
Water Jet ◽  
Boundary Layer Transition ◽  
Transition To Turbulence ◽  
Polymer Additives ◽  
High Speed Photography ◽  
Layer Transition ◽  
Spray Formation ◽  
Exit Surface

The effects of shape parameters on the performance of water-jet nozzles discharging in air were investigated using a camera specially adapted for jet photography. The boundary-layer developing on the exit surface of the nozzle is shown to account for the jet appearance revealed by high speed photography. Optimum nozzles seem to have the boundary-layer transition to turbulence inside the nozzle; transition outside the nozzle being accompanied by spray formation and early jet disruption. The effect of polymer additives seems to be earlier transition and a thinner turbulent boundary layer inside the nozzle which improves jet performance.

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