Analyses of an Ultrasonic Motor Driving Fluid Directly

Abstract

This paper presents an analysis of acoustic field and flow in an ultrasonic motor using fluid. The inside of a stator cylinder is filled with fluid. The fluid is caused to flow in the circumferential direction by the ultrasonic vibration traveling along the cylinder. It is revealed that shearing Reynolds' stress in the fluid is the driving force of the flow in this motor. According to the analytical method stated in this paper, we simulate and discuss some characteristics of this motor. In conclusion, the guideline for the optimum design of the motor is proposed, which is to tune the resonance frequency of the fluid field to that of the vibrating cylinder containing the fluid.