Broadband acoustic trapping of a particle by a soft plate with a periodic deep grating

TL;DR

This paper demonstrates broadband acoustic trapping of particles using a soft plate with a periodic deep grating, revealing a broad negative radiation force caused by surface wave resonance, with implications for particle manipulation.

Contribution

It introduces a soft-plate system with a periodic grating that achieves broadband negative acoustic radiation force for particle trapping, expanding the capabilities of acoustic manipulation.

Findings

Negative ARF confirmed for brass particles near soft plates

Broad bandwidth of negative ARF compared to stiff-plate systems

Negative ARF caused by gradient vortex velocity field from surface wave resonance

Abstract

We investigated the acoustic radiation force (ARF) acting on a cylindrical brass particle near an acoustically soft plate patterned with a periodic deep grating. The existence of a negative ARF by which the particle can be pulled towards the sound source is confirmed. In addition, the bandwidth for negative ARF in this soft-plate system is found to be considerably broader than in the stiff-plate systems typically used in previous studies. It is further demonstrated by field distribution analysis that the negative ARF is caused by the gradient force induced by the gradient vortex velocity field near the surface, which stems from the collective resonance excitation of the antisymmetric coupling of Scholte surface waves in the thin plate. The effects of particle location and size on the ARF were also investigated in detail. The negative ARF has potential use in applications requiring particle manipulation using acoustic waves.