Acoustically driven flow in flexural plate wave devices: theory and experiment

In this paper a theoretical and experimental investigation of the acoustic streaming that occurs in the fluid near a silicon-based, micromachined flexural plate wave (FPW) device is presented. A method of incorporating source boundary condition effects, which have been neglected in the past, into streaming theory is outlined briefly. This modified streaming theory is then applied to the problem in which the acoustic source is a thin plate with flexural waves traversing it. The source boundary effect in that case has a profound influence on the streaming flow, which is allowed to slip at the surface of the plate. Theoretical now profiles with velocity maxima of over 500 μm/s agree well with those that are measured in FPW devices