Specific impedance of liquids during ultrasonic cavitation

The macroscopic change in the specific impedance of a liquid was analyzed f rom a microscopic viewpoint on the basis of bubble dynamics. A shift of the electrical characteristics of an ultrasonic vibration system, whose acoust ical load includes a contribution from cavitating bubbles, was clarified an alytically. Namely, when the bubbles begin to collapse, the real part of th e specific impedance decreases gradually. On the other hand, the imaginary part rapidly becomes significant compared to the real part. Therefore, the liquid becomes a light acoustical load, and the amplitude of the electric a dmittance at the resonant increases rapidly. Moreover, the resonant frequen cy approaches that in a system without an acoustical load.