ABSTRACT
Cavitation, the rupture of liquids and its associated effects, is a much more general phenomenon than that caused by the propagation of an intense ultrasonic wave in a liquid. It can be engendered hydrodynamically (ship’s propellers, turbines, etc.) by absorption of a laser beam or by the passage of elementary particles in a liquid, among other possibilities. Oscillating bubbles in a liquid act as a point source of sound. At low drive levels, the bubble motion is linear and acoustic emission occurs at the fundamental frequency. As the acoustic power is increased, harmonics appear in the stable cavitation regime. Since bubbles are highly nonlinear acoustically, it is not surprising that a bubbly liquid is a highly dispersive and attenuating medium. The response of the medium is very important in areas such as oceanography and high-power ultrasonics in liquids.
