Taming acoustic cavitation

Abstract

In this fluid dynamics video we show acoustic cavitation occurring from pits etched on a silicon surface. By immersing the surface in a liquid, gas pockets are entrapped in the pits which upon ultrasonic insonation, are observed to shed cavitation bubbles. Modulating the driving pressure it is possible to induce different behaviours based on the force balance that determines the interaction among bubbles and the silicon surface. This system can be used for several applications like sonochemical water treatment, cleaning of surfaces with deposited materials such as biofilms [1].

Interplay Between Mechanochemistry and Sonochemistry

“…It is also worth mentioning that suitable cavitation nuclei may also be created at the expense of existing bubbles in a liquid or formed in crevices in suspended particles where very small amounts of gas can be trapped. An illustrative picture of this cascade process which involves several mechanisms that account for the mechanical action of ultrasonic waves is supplied in Figure 4 [28]. It is hoped that enhanced mechanical action will take place in association with high intensities and frequencies.…”