Transient flow in a rotating porous annulus due to suction at the walls

Abstract

A highly porous material occupies the annular region between two coaxial infinitely long cylinders. A viscous incompressible fluid fills this porous medium and is initially in a state of rigid rotation together with the medium. The flow has been disturbed by imposing suction/injection at the outer/inner cylindrical boundaries respectively. The Brinkman's law has been used to represent the fluid motion. The exact solution for the resulting unsteady flow is obtained by Laplace transformation technique. The transient evolution of the boundary layers and the response of steady boundary layers to the resistance of the medium are discussed.