Abstract

There are few objects in nature that interact with acoustic waves as effectively and efficiently as a gas bubble in a liquid. The velocity, intensity and even frequency content of sound waves are profoundly impacted by bubbles in suspension, and when high-pressure waves travel through a liquid medium, they nucleate small gas bubbles that subsequently respond to period acoustic forcing, a process known as acoustic cavitation. Cavitation bubbles convert acoustical energy to mechanical energy that is highly concentrated in both space and time. The result is a plethora of mechanical, and thermal effects, ranging from acoustic micro-streaming to extreme conditions at the point of cavity collapse. All of these effects play a role, to varying degrees, in a broad range of industrial and biomedical procedures involving ultrasound. In this talk, we present an introductory overview of the relevant bubble physics, physical effects, and the roles – both beneficial and detrimental – played by bubbles and cavitation in industrial and medical acoustics.