The scaling of acoustic streaming for application in micro-fluidic devices

Recent interest in MEMS devices in general, and in micro-fluidic devices specifically, has spurred a great deal of research into the behavior of fluids in very small-scale devices. Many novel techniques have been proposed for the propulsion of fluids in small scales devices including peristaltic and electrokinetic. More recently, investigations have considered the use of acoustic streaming: that is, the imposition of steady fluid momentum via nonlinear acoustic effects. The purpose of this manuscript is to overview the physics of acoustic streaming, discus the various physical phenomena which generate the effect, and to highlight the favorable scaling issues of acoustic streaming that make it a viable alternative in micro-fluidic devices.