Effects of Existence of Microbubbles for Increase of Acoustic Streaming

The effects of the existence of microbubbles in water on the increase of acoustic streaming velocity are experimentally investigated. The harmonics generated by the nonlinear vibration of microbubbles are regarded as the increase factor of the velocity. The streaming velocity was measured using a laser doppler velocimeter (LDV). To observe the effects of harmonics, a special tank was used. Microbubbles were generated by extracting water using the syringe mechanism. Experimental results clearly show that the acoustic streaming velocity is increased when microbubbles exist.