Free convection and mass transfer effects on the hydro-magnetic oscillatory flow past an infinite vertical porous plate

Two-dimensional unsteady free convection and mass transfer flow of an incompressible viscous dissipative and electrically conducting fluid, past an infinite, vertical porous plate, is considered, when the flow is subjected in the action of uniform transverse magnetic field. The magnetic Reynolds number is taken to be small enough so that the induced magnetic field is negligible. The solution of the problem is obtained in the form of power series of Eckert number E, which is very small for incompressible fluids. Analytical expressions for the velocity field and temperature field are given, as well as for the skin friction and the rate of heat transfer for the case of the mean steady flow and for the unsteady one. The influence of the magnetic parameter, M, modified Grashof number Gsub(c), Schmidt number Ssub(c) and frequency ω, on the flow field, is discussed with the help of graphs, when the plate is being cooled, by the free convection corrents (Gsub(r)sub(,)E > 0), or heated (Gsub(r)sub(,)E < 0). A comparative study with hydrodynamic case (M not equal 0) and the hydromagnetic one (M not equal 0) is also made whenever necessary. (orig.)