Edge-induced radiation force and torque on a cylindrically-radiating active acoustic source near a rigid corner-space

TL;DR

This paper analyzes how an active acoustic source near a rigid corner experiences radiation force and torque, revealing conditions for motion suppression and potential for controlled pushing, pulling, or spinning effects.

Contribution

It provides exact closed-form expressions for radiation force and torque on a radiating source near a corner, using modal series, image method, and addition theorem, advancing understanding of acoustic manipulation.

Findings

Conditions where force and torque vanish, enabling motion suppression.

Dependence of force and torque direction on source size and distance.

Potential for controlling source motion and rotation near corners.

Abstract

This work examines the physical effect of the edge-induced acoustic radiation force and torque on an acoustically radiating circular source, located near a rigid corner. Assuming harmonic (linear) radiating waves of the source, vibrating in monopole or dipole radiation modes near a rigid corner-space in a non-viscous fluid, the modal series expansion method in cylindrical coordinates, the classical method of images and the translational addition theorem are applied to obtain the mathematical expressions for the radiation force and torque components in exact closed-form partial-wave series. Computational results illustrate the theory, and examine some of the conditions where the radiation force and torque components vanish, which has the potential to achieve total motion suppression (i.e., translation or rotation). Furthermore, depending on the size parameter of the source and the distances from the rigid corner space, these physical observables take positive or negative values, anticipating the prediction of pulling/pushing motions toward the corner space, and possible spinning of the source clockwise or counter-clockwise. The present analysis and its results are useful in some applications related to the manipulation of an active carrier or ultrasound contrast agents near a corner space or chamber walls at a right angle.