UNSTEADY MHD FLOW NEAR A ROTATING POROUS DISK WITH UNIFORM SUCTION ORINJECTION

In this paper, the MHD flow of an incompressible, viscous and electric ally conducting fluid above an infinite rotating porous disk is extend ed to flow starting impulsively from rest. The fluid is subjected to a n external uniform magnetic field perpendicular to the plane of the di sk. The effects of uniform suction or injection through the disk on th e unsteady MHD flow are also considered. The governing nonlinear parti al differential equations are solved numerically using the finite-diff erence approximations with a special treatment of the discontinuity be tween the initial and boundary conditions. The results of the numerica l solution indicate some interesting effects of the magnetic field and the suction or injection velocities on the flow and prove that the st eady state can be reached via a time-dependent process. (C) 1998 The J apan Society of Fluid Mechanics and Elsevier Science B.V. All rights r eserved.