scholarly journals Comparison of cavitation bubbles evolution in viscous media

2018 ◽  
Vol 180 ◽  
pp. 02038 ◽  
Author(s):  
Darina Jasikova ◽  
Petr Schovanec ◽  
Michal Kotek ◽  
Vaclav Kopecky
Keyword(s):  
Cavitation Bubble ◽  
High Speed ◽  
Silicone Oil ◽  
Time Development ◽  
High Speed Camera ◽  
Silicon Oil ◽  
Cavitation Bubbles ◽  
Laser Induced Breakdown ◽  
Viscous Media ◽  
Superheat Limit

There have been tried many types of liquids with different ranges of viscosity values that have been tested to form a single cavitation bubble. The purpose of these experiments was to observe the behaviour of cavitation bubbles in media with different ranges of absorbance. The most of the method was based on spark to induced superheat limit of liquid. Here we used arrangement of the laser-induced breakdown (LIB) method. There were described the set cavitation setting that affects the size bubble in media with different absorbance. We visualized the cavitation bubble with a 60 kHz high speed camera. We used here shadowgraphy setup for the bubble visualization. There were observed time development and bubble extinction in various media, where the size of the bubble in the silicone oil was extremely small, due to the absorbance size of silicon oil.

scholarly journals Numerical Study of the Pulsation Process of Spark Bubbles under Three Boundary Conditions

2021 ◽  
Vol 9 (6) ◽  
pp. 619
Author(s):  
Chunlong Ma ◽  
Dongyan Shi ◽  
Chao Li ◽  
Dongze He ◽  
Guangliang Li ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Nonlinear Interaction ◽  
Cavitation Bubble ◽  
High Speed ◽  
Free Field ◽  
Experimental Results ◽  
High Speed Camera ◽  
Cavitation Bubbles ◽  
Bubble Pulsation

In this study, a compressible three-phase homogeneous model was established using ABAQUS/Explicit. These models can numerically simulate the pulsation process of cavitation bubbles in the free field, near the flat plate target, and near the curved boundary target. At the same time, these models can numerically simulate the strong nonlinear interaction between the cavitation bubble and its nearby wall boundaries. The mutual flow of liquid and gas and fluid solid coupling were solved by the Euler domain in simulation. The results of the numerical simulation were verified by comparing them with the experimental results. In this study, we used electric spark bubbles to represent cavitation bubbles. A high-speed camera was used to record the pulsation process of cavitation bubbles. This study first verified the pulsation process of cavitation bubbles in the free field, because it was the simplest case. Then we verified the interaction process between cavitation bubbles and different wall boundaries. In order to further confirm the credibility of the numerical simulation results, for each wall surface, this study used two burst distances (10 mm and 25 mm) for simulation verification. The numerical model established in this study could effectively simulate the pulsation characteristics of cavitation bubbles, such as the formation of jets and annular bubbles. After verification, the simulated cavitation bubble was almost the same as the cavitation bubble captured by the high-speed camera in the experiment in terms of time, volume, and shape. In this study, a detailed velocity field of the cavitation bubble collapse stage was obtained, which laid down the foundation for the study of the strong nonlinear interaction between the cavitation bubble and the target plates of different shapes. Compared with the experimental results, we found that the numerical model established by the simulation could accurately simulate the bubble pulsation and jet formation processes. In the experiment, the interval time for the bubble pictures taken by the high-speed camera was 41.66 μs per frame. Using a numerical model, the bubble pulsation process can be simulated at an interval of 1 µs per frame. Therefore, the numerical model established by the simulation could show the movement characteristics of the cavitation bubble pulsation process in more detail.

scholarly journals Sterilization of Biofilm in Foam Using a Single Cavitation Bubble

2020 ◽  
Vol 328 ◽  
pp. 05003
Author(s):  
Petr Schovanec ◽  
Darina Jasikova ◽  
Michal Kotek ◽  
Karel Havlicek ◽  
Magda Nechanicka ◽  
...  
Keyword(s):  
Laser Beam ◽  
Cavitation Bubble ◽  
High Speed ◽  
Bubble Collapse ◽  
Long Distance ◽  
Piv Method ◽  
Cavitation Bubbles ◽  
Image Velocimetry ◽  
Laser Induced Breakdown ◽  
Surrounding Liquid

This article presents the sterilization of bacteria using cavitation bubbles. Cavitation generated by ultrasound creates a cavitation cloud. Therefore is more advantageous to generate the cavitation bubbles by laser-induced breakdown, because it is possible to generate individual bubbles for the purpose of study single impact and physical mechanism of acting. The cavitation bubble is generated by a Nd: YAG 532nm laser beam, a short 10ns pulse. Here, we used optics to focus the laser beam and a high-speed camera to visualize characteristics the bubble. We used the method of long-distance microscopy and shadowgraph lightening for the visualization. We used the particle image velocimetry (PIV) method to determine the interaction of the bubble with the surrounding liquid and solid surface. The main goal of the research is to use cavitation to sterilize bacteria and biofilm in impact of single bubble collapse on living cells.

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.

scholarly journals APPLICATION OF LASER-INDUCED BREAKDOWN CAVITATION BUBBLES FOR CELL LYSIS IN VITRO

2019 ◽  
pp. 186-190
Author(s):  
DARINA JASIKOVA ◽  
MIROSLAVA RYSOVA ◽  
MICHAL KOTEK
Keyword(s):  
Cavitation Bubble ◽  
Laser Energy ◽  
Cell Lysis ◽  
Basic Mechanism ◽  
Free Cell ◽  
Cavitation Bubbles ◽  
Optical Visualization ◽  
Laser Induced Breakdown ◽  
The Impact

Objective: Understanding the basic mechanism of the cavitation bubble action on living cells as a crucial step of development and application ofsophisticated methods based on controlled cavitation in cell behaviour manipulation. Optimisation of parameters in order to expand cell lysis regioncreated by a single bubble.Methods: The cavitation bubbles are generated by the laser-induced breakdown method. The impact of controlled cavitation bubble on thebiological system is synchronously monitored under a microscope and recorded. Visualization of the cavitation bubble course is monitored by a highspeedcamera. The impact of technology on the healthy confluent cell layer is verified. Evaluation of the cavitation bubbles´ effect on cells in real timeand by subsequent analysis of the cell lysis region and impact of the cavitation bubble on cell viability is carried out by optical visualization and life/dead fluorescence staining.Results: Cavitation bubble induced in distance of 1.5 mm from the cell surface overcomes properties of sessile bubble and enables to create cell lysisregion over 1000 μm in diameter due to transient shear stress produced by liquid displaced by the bubble expansion.Conclusion: Cell lysis region is strongly dependent on the spot laser energy (SLE) and the bubble induction distance from cells. This knowledge iscrucial for application in chemical free cell lysis in vitro, wound induction for experimental purposes and cell layers patterning in desired scale.

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 Fission of collapsing cavitation bubbles

2002 ◽  
Vol 472 ◽  
pp. 153-166 ◽  
Author(s):  
CHRISTOPHER E. BRENNEN
Keyword(s):  
Stability Analysis ◽  
Cavitation Bubble ◽  
High Speed ◽  
The Other ◽  
Single Bubble ◽  
Minimum Size ◽  
Fission Process ◽  
Fission Fragments ◽  
Flow Parameters ◽  
Cavitation Bubbles

High-speed observations clearly show that though a collapsing cavitation bubble approaches its minimum size as a coherent single volume, it usually reappears in the first rebounding frame as a cloud of much smaller bubbles or as a highly distorted single volume. This paper explores two mechanisms that may be responsible for that bubble fission process, one invoking a Rayleigh–Taylor stability analysis and the other using the so-called microjet mechanism. Both approaches are shown to lead to qualitatively similar values for the number of fission fragments and the paper investigates the flow parameters that effect that number. Finally, the additional damping of the Rayleigh–Plesset single-bubble calculation caused by the fission process is investigated; it is shown that the fission damping dominates other contributions normally considered and is consistent with the number of collapses and rebounds that are observed to occur in experiments.

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