Unsteady flow of an incompressible fluid in a horizontal porous medium with suction

A theoretical analysis of two-dimensional unsteady flow in a porous medium bounded by a horizontal wall is presented as a perturbation on a basic flow. It is assumed that the perturbation is occasioned by a sudden suction at the wall. Even for a highly permeable medium, the characteristic Reynolds number in porous media flow is usually small and asymptotic solutions are developed by the Laplace transform technique. It is observed that the perturbed shear stress at the wall decays exponentially with time