Interaction of a strong shockwave with a gas bubble in a liquid medium: a numerical study

Abstract

The interaction of a shockwave with a gas bubble in a liquid medium is of interest in a variety of areas, e.g. shockwave lithotripsy, cavitation damage and the study of sonoluminescence. This study employs a high-resolution front-tracking framework to numerically investigate this phenomenon. The modelling paradigm is validated extensively and then used to explore the parametric space of interest. We provide a comprehensive qualitative analysis of the collapse process, which we categorize into three phases, based on the principal feature dominating each phase. This results in the characterization of numerous previously unidentified features important in the evolution of the process and in the emergence of peak temperatures and pressures. For example, we discover that the peak pressure does not occur as a result of the impact of the main transverse jet (also called the re-entrant jet) but later in the collapse. We perform fully three-dimensional simulations, showing that three-dimensional instabilities are limited to the small-scale details of collapse, and continue by comparing collapse of cylindrical and spherical bubbles. We detail a parametric investigation varying the shock strength from 100 MPa to 100 GPa. A counter-intuitive discovery is that the maximum gas density decreases with increasing shock strength.

Prediction of far-field acoustic emissions from cavitation clouds during shock wave lithotripsy for development of a clinical device

“…Apart from the free-Lagrange studies cited above and the work by Hawker & Ventikos [42] that used a high-resolution front-tracking method to study a shock-bubble interaction, earlier simulations had also included loss of sphericity and jets, but not compressibility or bubble fragmentation. Consequently, they operated on a time scale that was restricted to the early periods of the cavitation event, before these effects became important [43][44][45].…”

Dynamics of laser-induced bubble pairs

“…In the case of a bubble collapsing in a stationary liquid near a solid boundary, the jet is directed towards the boundary and reaches velocities of the order of 100 m s −1 (Benjamin & Ellis 1966;Plesset & Chapman 1971;Lauterborn & Bolle 1975;Blake, Taib & Doherty 1986;Tomita & Shima 1986;Blake & Gibson 1987;Vogel, Lauterborn & Timm 1989;Zhang, Duncan & Chahine 1993;Shaw et al 1996;Tong et al 1999;Brujan et al 2002;Popinet & Zaleski 2002;Lindau & Lauterborn 2003;Johnsen & Colonius 2009;Ochiai et al 2011). Jet formation is also observed with bubbles compressed by a shock wave (Bowden 1966;Dear, Field & Walton 1988;Bourne & Field 1992Antkowiak et al 2007;Hawker & Ventikos 2012). Depending on the strength of the incident shock wave, jet velocities of the order of 1000 m s −1 are reported.…”

“…An artificial liquid with the properties of water, except for the sound velocity, is chosen. The reason is that upon laser bubble formation a strong shock wave is radiated that presents problems in being properly captured by the numerical code (see the efforts that Hawker & Ventikos (2012) have undertaken to solve the problem of the interaction of a shock wave with a bubble). Therefore, linear acoustics and a reduced sound speed are used for the liquid, for definiteness that of the gas.…”

Modeling asymmetric cavity collapse with plasma equations of state

“…Previous efforts by the current authors examine the detailed asymmetric collapse of a polytropic air cavity in water when struck by a planar shock wave across a range of intensities. The incident shock was varied from 0.1 to 100 GPa and peak densities and temperatures in the gas reached conditions in the order of 1 g/cm 3 and 10 eV [11]. The hydrodynamics of the simulated collapse processes showed excellent agreement with available experimental literature; however, the achieved conditions exceed the validity of the ideal gas equation of state (EOS).…”

“…Asymmetric cavity collapse-characterized by the formation of a main transverse jet [11]-is a hydrodynamically very different process to SBSL that can achieve a different set of thermodynamic conditions. Intensification provided through spherical symmetry is sacrificed, yet the collapse maintains various significant energy focusing processes.…”