Acoustic radiation force on a particle in a temperature gradient

Abstract

A general expression is derived for the acoustic radiation force on a small spherical particle of radius R in a standing wave field in a temperature gradient.The case of a particle inside a long tube chamber with a temperature gradient along the axis of symmetry is examined in more detail. The analysis is considerably simplified by the introduction of the mass flux density potential ψ. Assuming kR≪1, and neglecting convection, acoustic streaming, heat conduction, and viscosity effects, an expression is obtained for the force that consists of a ‘‘local’’ version of Gor’kov’s result as well as correction terms of order β/k, where β∼(1/T)(dT/dz).