Effect of Vibration Plate Shape on Acoustic Viscous Stress in Near-field Acoustic Levitation

Abstract

This study concerns the design of non-contact handling devices based on near-field acoustic levitation. In the near-field acoustic levitation, a holding force acts on the levitated object, and the lateral position of the levitated object is stably maintained. This holding force is caused by the acoustic viscous stress which can be calculated from the sound pressure distribution. In this paper, a calculation model using the boundary element method (BEM) is proposed to obtain the sound pressure distribution near the levitated plate, and the relationship of the lateral displacement and holding force is computed by using the proposed model. Then, the validity of the calculation model is evaluated by comparing the numerical results with the experimental results in the literature. As a result, it is shown that the proposed calculation method can be used for the analysis of the near-field acoustic levitation, particularly the evaluation of the holding force acting on the levitated objects.