Chemical reaction and radiation effects on the transient MHD free convection flow of dissipative fluid past an infinite vertical porous plate with ramped wall temperature

A finite-difference analysis is performed to study the effects of thermal radiation and chemical reaction on the transient MHD free convection and mass transform flow of a dissipative fluid past an infinite vertical porous plate subject to ramped wall temperature. The fluid considered here is a gray, absorbing/emitting radiation but a non-scattering medium. The dimensionless governing equations are unsteady, coupled and non-linear partial differential equations. An analytical method fails to give a solution. Hence an implicit finite difference scheme of Crank-Nicolson method is employed. The effect of the Magnetic parameter (M), Chemical reaction parameter (K), Radiation parameter (F), Buoyancy ratio parameter (N), Schmidt number (Sc) on the velocity field and skin friction for both air (Pr=0.71) and water(Pr=7) in the presence of both aiding (N>0) and opposing (N<0) flows are extensively discussed with the help of graphs.