Probing the limit between spherical and deformed cavitation bubbles*

Experiments were conducted to explore the transition between spherical and aspherical collapses of single cavitation bubbles. Using two piezoelectric hydrophones and a high-speed photodetector, we recorded the time sequence of the shock waves and luminescence emitted at the collapse of laser-induced bubbles to obtain a precise measure of their displacement during their lifetime. Additionally, we quantified the asymmetry of the shock waves generated at the collapse of bubbles with various levels of deformations, and found important differences between the pressures measured at two different locations. The results further consolidate the utility of the Kelvin impulse in predicting the behavior of jetting cavitation bubbles.