Abstract

An exact solution to the problem of a transient free convective mass transfer flow of a Newtonian non-Grey optically thin fluid past a suddenly started infinite vertical plate embedded in a porous medium with ramped wall temperature as well as ramped plate velocity in presence of appreciable thermal radiation and first-order chemical reaction is presented. The resulting system of equations governing the flow is solved by employing Laplace Transform technique in closed form. Detailed computations of the influence of ramped velocity parameter A, radiation parameter Q, Reynolds number Re, Schmidt number Sc, porosity parameter S and chemical reaction parameter K on the variations in the fluid velocity, fluid temperature, fluid concentration, and skin friction, Nusselt number  and Sherwood number at the plate are demonstrated graphically. The results show that the effect of the ramped parameter A accelerates the fluid flow substantially. Further, our investigation reveals the fact that the viscous drag at the plate gets increased due to chemical reaction in case of ramped plate temperature. Comparison of some of the results of the present work is made with previously published results under special cases, and shows a good agreement.

Key words: Ramped plate velocity, ramped plate temperature, thermal radiation, chemical reaction, optically thin, porosity.