Radiation pressure of sound on moving vortices

Abstract

This report is devoted to the nonlinear acoustic pressure of sound waves propagating in the vicinity of a rather general class of localized flows induced by the motion of spherically symmetric structures of the type of vortices in the liquid, say, ocean environment. As a result, the mean force exerted on a vortex is considered. The conventional general expression for transport cross section derived in a nonlinear theory of interaction of sound with rigid particles is proven to be incorrect for the vortex–sound interaction case. For the specific case of Hill’s vortex mean force, it is shown to be absent both in the traveling and standing sound wave fields. However, the force could be observable if the distribution of mean sound energy in the incident sound field in the limit of vortex dimensions could be characterized by nonzero spatial gradient. A generalized expression for mean force exerted on a localized vortex structure is derived.