Characterization as measurement sound source of acoustic cavitation noise from bubble clusters under ultrasonic horn

Abstract

In order to investigate the possibility of using acoustic cavitation noise generated by ultrasonic horns as an acoustic measurement signal, its directional characteristics, autocorrelation characteristics, and frequency characteristics are investigated with a hydrophone and schlieren visualization. In addition, a parabolic mirror is used to shape the spherical acoustic cavitation noise into a plane wave. As a result, it is found that the acoustic cavitation noise consists of a spherical shockwave pulse train and has a frequency bandwidth of at least 10 MHz and sharp autocorrelation characteristics. Furthermore, it is also shown that a parabolic mirror can shape a spherical shockwave into a plane shockwave.