Effect of surface irregularities on the stability of Stokes boundary

Abstract

In this work, we examine that impact that wall surface roughness plays on the stability of an oscillatory Stokes boundary layer. The temporal growth of three-dimensional disturbances excited by wall height variations is of particular interest. Floquet theory is used to identify linearly unstable region in parameter space. It is shown that disturbances become unstable at critical value of the Taylor number for a given surface curvature. The case of oscillatory flow in a two-dimensional rigid walled channel is considered in detail.