Effect of Ultrasonic Vibrations on Fluid Flow in a Channel. Turbulence Promotion by Ultrasonic Vibration.

Abstract

The flow pattern by ultrasonic vibration in a square channel was investigated as basic research into fluid control without contact. A turbulence promoter by ultrasonic vibration was proposed in this experiment. An ultrasonic transducer was fixed to the bottom of a square test channel, and a standing wave field was formed in this channel. The ultrasonic oscillators are bolted Langevin PZT-type vibrators with resonance frequencies of 25.4kHz and 44.21kHz and ultrasonic power varies in a range of 10W to 80W. The fluid velocity was measured by a Laser-Doppler velocimeter. By applying the ultrasonic vibrations into the laminar flow, the flow pattern in the channel was developed by the agitation or turbulence of cavitation bubbles, which consequently, changed from a laminar flow into a uniform flow. Since it is possible to control the the fluid flow from outside due to the easy transmission of ultrasonic vibration in liquid, this technique can be applied to fluid flow in various channels as a non-contacting turbulence promoter.