Liquid Streaming by High-Frequency Ultrasonic Waves

Abstract

Liquid streaming induced by ultrasonic waves in VHF range is discussed. Theoretical analysis shows that the radiation pressure and net body force caused by liquid streaming are proportional to the second and the fourth power of frequency, respectively. Experiments were performed using a ZnO-film/cover-glass composite transducer operated at 241 MHz. Strong liquid streaming was observed and the water surface above the transducer was lifted to 5 mm with the acoustic power of 40 mW. This value roughly agreed with the theoretical prediction.