Acoustic Streaming

Acoustic streaming is steady fluid flow produced by conservation of momentum associated with the absorption of sound. The basic equations are obtained by time-averaging the momentum equation with shear and bulk viscosity included. A volume integral for streaming in a free field produced by an arbitrary sound field is used to obtain a solution for streaming generated by a focused sound beam. Streaming produced by the viscous boundary layer acting on a plane traveling wave that grazes a wall is described. Distinctions are made between Eulerian, Lagrangian, and mass transport streaming velocities. The chapter concludes with applications of acoustic streaming.