Bubble collapse and rebound in a diagnostic ultrasonic field

Abstract

The influence of the finite-amplitude distortion of a driving diagnostic ultrasonic field on the collapse and rebound of a gas-filled spherical microbubble in a compressible liquid is investigated. It is noted that one of the mechanisms for cavitation damage comes from the very large gas pressures generated at bubble collapse and in the subsequent pressure wave formed by bubble rebound. Numerical results show that the strength of the pressure spikes radiated by the rebounding bubble depends on (i) the acoustic frequency, (ii) the initial bubble size, and (iii) the magnitude of the pressure amplitude of the fundamental in a Fourier series description of the distorted pulse. As the pressure spikes propagate outward from the bubble wall, their strength is attenuated as the reciprocal of the distance from the center of collapse. >