Simulation of the flow induced by acoustic streaming in noncontact ultrasonic motors

In order to overcome many shortcomings of the traditional contact-type rotors, noncontact ultrasonic motors, which are driven by acoustic streaming, have been proposed. Recently, an analytical solution based on the second order approximation has been presented, but it gives a revolution speed five times smaller than the experimental value. In order to reconcile the discrepancy, the authors perform numerical simulations of the gas motion between the stator and the rotor driven by the acoustic streaming. With the same parameters used in the experiment, it is found that the acoustic streaming can account for the observed fast rotation. (c) 2007 American Institute of Physics.