The final stage of the collapse of a cavitation bubble close to a rigid boundary

Abstract

The final stage of the collapse of a laser-produced cavitation bubble close to a rigid boundary is studied both experimentally and theoretically. The temporal evolution of the liquid jet developed during bubble collapse, shock wave emission and the behavior of the ''splash'' effect are investigated by using high-speed photography with up to 5 million frames/second. For a full understanding of the bubble-boundary interaction, numerical simulations are conducted by using a boundary integral method with an incompressible liquid impact model. The results of the numerical calculations provided the pressure contours and the velocity vectors in the liquid surrounding the bubble as well as the bubble profiles. The comparisons between experimental and numerical data are favorable with regard to both bubble shape history and translational motion of the bubble. The results are discussed with respect to the mechanism of cavitation erosion.

Dynamics of laser-induced bubble pairs

“…The interaction of a bubble with its environment generically establishes an asymmetry that, for strong interaction, leads to jet formation, whereby the bubble pierces itself with a high-speed liquid jet. 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).…”

Cavitation Bubble Dynamics inside Liquid Drops in Microgravity

“…Fundamental understanding requires studies of single bubbles in different liquid geometries, since bubble dynamics strongly depends on nearby surfaces by means of boundary conditions imposed on the surrounding pressure field [1,6]. Recent investigations revealed interesting characteristics of bubbles collapsing next to flat [7] and curved [8] rigid surfaces or flat free surfaces [9,10]. It is thus a promising idea to study bubbles inside spherical drops and probe their interaction with closed spherical free surfaces.…”

Asymmetric oscillation of adherent targeted ultrasound contrast agents

“…18,21 For a bubble with an initial radius of 5 microns and wall velocity of 12 m/s, in a microvessel with a diameter of 200 microns, the ratio of (a-b)/a was estimated to be ∼2.5%, where a and b are the semimajor and semiminor axes of an ellipse, respectively. 22 In our experimental study in a 200 micron microvessel, bubbles were adherent to the boundary rather than located in the center of the microvessel, and the acoustic pressure used resulted in a higher maximum wall velocity, estimated to be on the order of 50 m/s at 240 kPa.…”

“…15 In these studies, a microbubble is assumed to remain spherical and in an infinite medium. Asymmetrical oscillation of a cavitation bubble and formation of a jet have been studied both theoretically and experimentally by a number of research groups, [16][17][18] although previous experimental studies have involved unencapsulated bubbles of a diameter larger than micron-sized contrast agents, and have not used ultrasound as an excitation source. The behavior of a targeted microbubble after it binds to a vessel wall and is insonified by an ultrasound pulse has not been reported previously.…”