FREE AND FORCED CONVECTIVE MHD OSCILLATORY FLOW OVER AN INFINITE POROUS SURFACE IN AN OSCILLATING FREE STREAM

This paper deals with the mixed convection hydromagnetic oscillatory flow and periodic heat transfer of a viscous incompressible and electrically conducting fluid past an infinite vertical porous plate. The plate is subjected to a constant suction velocity and heat absorbing sinks, while the free stream is oscillating with time. A magnetic field of uniform strength is applied in the direction normal to the plate. The transient, nonlinear and coupled governing equations are solved using multi-parameter perturbation technique. Approximate solutions have been derived for the velocity and temperature fields as well as mean skin-friction and mean rate of heat transfer. It is found that, the increase in magnetic field strength leads to decrease transient velocity as well as temperature. Further, the amplitude (vertical bar H vertical bar) as as phase (tan beta) of the mean rate of heat transfer increases with increasing magnetic field strength (M) for electrolytic solution (Pr=1.0), while a reverse phenomenon is observed for mercury (Pr=0.025).