The evolution of the cavitation bubble driven by different sound pressure

In this paper, the relation between the ambient radius R(0) of the acoustic cavitation bubble and its driving pressure was investigated by an improved method. The evolution of the bubble was gained with a long-distance microscope and a bundle of 532 nm laser switched by an acousto-optic modulator. The ambient radius R(0) was determined by fitting the numerical calculation based on Rayleigh-Plesset equation to the experimental data. The results showed that as the sound pressure increased R(0) decreased at beginning and increased after the pressure reached to about 1.2 atm. Although the same rule was gotten from the relation between the maximum radius R(m) and the sound pressure, the ratio R(m)/R(0) varied monotonously with the sound pressure. It indicates that enhancing the sound pressure can increase the compression ratio of the bubble even if the mass inside the bubble is also increased.