Thermal diffusion effect on unsteady MHD free convective flow past a semi-infinite exponentially accelerated vertical plate in a porous medium

Abstract

The objective of the present work was to obtain an exact solution to the problem of a free convective, radiative, viscous, chemically reacting, heat-absorbing, incompressible, and unsteady magnetohydrodynamic flow past an exponentially accelerated moving vertical plate embedded in a porous medium. The fluid was assumed to be optically thick and nongray. A magnetic field was applied in the transverse direction of the flow. Effects of arbitrary ramped temperature and thermal diffusion were also considered. The Rosseland approximation method was used to describe the radiative heat flux that appears in the energy equation. Analytical solutions of the nondimensional governing equations were obtained by adopting a closed form of the Laplace transformation technique. The influence of various physical parameters on flow and transport characteristics was analyzed with suitable graphs. From the investigation, it was observed that increasing the Soret number increased both the concentration and velocity fields. Increasing the radiation parameter caused an upsurge in the Nusselt number but reduced the Soret number.