Acoustically-driven cloud cavitation of coated microbubbles
Fluid Mechanics
Final Report Abstract
The primary focus of this project was the modeling of acoustic emissions of cavitation bubbles, with the aim of predicting the pressure, velocity and temperature in the vicinity of cavitation bubbles accurately and efficiently. The combination of a newly developed single-bubble model in compressible liquids and a novel Lagrangian wave tracking method makes it now possible, to study the acoustic emissions as well as the induced flow field and temperature distribution faithfully and rapidly. With this new computational tool, we gathered new insights into the pressure, velocity and temperature distribution in the vicinity of acoustically-driven lipid-coated microbubbles and other cavitation bubbles. This was accompanied by fullyresolved simulations of asymmetric cavitation bubble collapse, and progress in modeling discrete bubbles in Euler-Lagrange frameworks. The improved understanding of acoustic emissions of cavitation bubbles, in conjunction with numerical methods, provides a critical resource for the future development of medical treatments that exploit the localized and tuneable energy focusing of microbubbles, as well as emerging treatments utilizing nanobubbles and nanodroplets. The curiosity sparked by the strongly nonlinear acoustic emissions observed during cavitation led us to study nonlinear acoustic waves emitted by moving walls in more detail. With our newly developed a new finite-different method for this purpose, it is now possible to study the modulation of acoustic waves emitted by moving boundaries and in non-uniform flows. The acoustic black hole analogue developed as a result of this effort points to a previously unknown modulation mechanism of acoustic waves in accelerating flow, which opens the door for new engineering applications, such as in remote sensing and acoustic cloaking.
Publications
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Modelling Lipid-Coated Microbubbles in Focused Ultrasound Applications at Subresonance Frequencies. Ultrasound in Medicine & Biology, 47(10), 2958-2979.
Gümmer, Jonas; Schenke, Sören & Denner, Fabian
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Multiscale modeling and validation of the flow around Taylor bubbles surrounded with small dispersed bubbles using a coupled VOF-DBM approach. International Journal of Multiphase Flow, 141, 103673.
Cerqueira, Rafael F.L.; Paladino, Emilio E.; Evrard, Fabien; Denner, Fabian & Wachem, Berend van
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Propagation and modulation of nonlinear spherical waves emitted from oscillating bubbles, 74th Annual DFD Meeting of the American Physical Society, 21-23 November 2021, Phoenix, AZ, USA.
S. Schenke, F. Sewerin, B. van Wachem & F. Denner
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The acoustic pressure generated by the cavitation bubble expansion and collapse near a rigid wall. Physics of Fluids, 33(3).
Gonzalez-Avila, Silvestre Roberto; Denner, Fabian & Ohl, Claus-Dieter
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The Gilmore-NASG model to predict single-bubble cavitation in compressible liquids. Ultrasonics Sonochemistry, 70, 105307.
Denner, Fabian
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Acoustic black hole analogy to analyze nonlinear acoustic wave dynamics in accelerating flow fields. Physics of Fluids, 34(9).
Schenke, S.; Sewerin, F.; van Wachem, B. & Denner, F.
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Explicit predictor–corrector method for nonlinear acoustic waves excited by a moving wave emitting boundary. Journal of Sound and Vibration, 527, 116814.
Schenke, Sören; Sewerin, Fabian; van Wachem, Berend & Denner, Fabian
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Numerical prediction of acoustic wave dynamics in moving fluids and acoustic black holes, 92nd Annual Meeting of the International Association of Applied Mathematics and Mechanics (GAMM), 15-19 August 2022, Aachen, Germany.
S. Schenke, F. Sewerin, B. van Wachem & F. Denner
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Predicting acoustic emissions of ultrasound-driven lipid-coated microbubbles, 182nd Meeting of the Acoustical Society of America, 23-27 May 2022, Denver, CO, USA.
S. Schenke, R. Saha & F. Denner
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Modeling acoustic emissions and shock formation of cavitation bubbles. Physics of Fluids, 35(1).
Denner, Fabian & Schenke, Sören
