Calculation of linear stability of fluid flow in a flat channel with walls wavy across the flow

Abstract

Using the full Navier-Stokes equations, the linear stability of a plane Poiseuille flow in a channel with a corrugated bottom wall is considered. The wall is corrugated across the flow, and the main flow has one velocity component. The perturbations of the velocity and pressure fields are three-dimensional with two wave numbers. The generalized eigenvalue problem is solved numerically. It is found that the critical Reynolds number, above which time-increasing disturbances appear, depends in a complex way on the dimensionless amplitude and the corrugation period. The magnitude of the ratio of the amplitude and the corrugation period divides the area of the dimensionless amplitude of the corrugation into two, where the dependences of the critical Reynolds number on the parameters of the corrugation are qualitatively different.