The pulsation and translation of two cavitation bubbles are studied numerically in sound field. The results show that bubbles’ pulsation driven by the sound makes them translate. Different pulsations lead to different translations. Two bubbles will be mutually attractive to each other if they pulsate in phase, while they will be repulsive if out of phase. Furthermore, the secondary Bjerknes force for small phase difference is attractive, and it becomes repulsive for other phase differences up to π phase difference due to the nonlinear effect, although the attractive strength between two bubbles is much larger than the repulsive strength. Finally, one bubble pulsation and the other bubble stationary make the bubbles repel each other.

No abstract

A lattice model is introduced to deal with the dynamics of bubbles in cavitation cloud driven by ultrasound, which makes it possible to extend the study of a finite number of bubbles to cloud with an infinite number of bubbles. In this model, the arrangement of bubbles in cloud is assumed to be a cubic lattice. The central bubble in one lattice cell is representative of all the bubbles in cloud. The numerical simulation shows that the bubble in cloud can be severely suppressed by other bubbles under a cubic lattice structure. An interesting phenomenon is found that the maximum radius of bubbles would be saturated when the driving amplitude exceeds a threshold in cavitation cloud, which makes it easy to understand that the sonoluminescence in a single bubble is always brighter than that in cloud.