An analysis of a two-dimensional, unsteady flow of an electrically conducting, viscous, incompressible rarefied gas past an infinite vertical porous plate is carried out under the following assumptions: (i) the suction velocity normal to the plate is constant (ii) the fiee stream velocity oscillates in time about a constant mean (iii) the plate temperature is constant (iv) the difference between the temperature of the plate and the free stream is moderately large causing the free convection currents (v) first order velocity-slip and the temperature jump boundary conditions (vi) transverse magnetic field (vii) induced magnetic field is negligible.
Approximate solutions to the coupled, non-linear equations governing the flow are derived for the mean velocity, mean temperature, mean-skin-friction, mean rate of heat transfer, transient velocity and temperature, fluctuating parts of the velocity profiles, the amplitude and the phase of the skin-friction and the rate of heat-transfer. They are shown graphically followed by a discussion. The effects of ยฑ G (Grashof number), ยฑ E (Eckert number), M (Magnetic field parameter), h~ (rarefaction parameter), h 2 (temperature jump coefficient), cn (frequency) are discussed for heating (G < 0) or cooling (G > 0) of the plate by the free convection currents. Nomenclature ]B] amplitude of skin-friction B o applied magnetic field cp specified heat at constant pressure -49 -