Determination of velocity, size and concentration of ultrasonic cavitationbubbles by the phase-Doppler technique

An experimental study about the velocity, size and concentration of ultraso nic cavitation bubbles is presented. Ultrasound is provided from a 20 kHz h orn dipping vertically into a liquid container. Using the laser phase-Doppl er technique, cavitation bubble velocity and size distributions are obtaine d at various locations inside the ultrasound field. Axial and radial profil es of average bubble velocity, mean diameters and volumetric flow rate are presented. The influence of ultrasound power input is also investigated: it increases bubble velocity quasi-linearly and has more complex effect on bu bbles diameter. The system investigated possesses similar hydrodynamic prop erties with typical turbulent circular jet flows. (C) 2001 Published by Els evier Science Ltd.