ABSTRACT
An analysis has been carried out to study the effects of thermal radiation and chemical reaction of MHD natural convection flow of a viscous incompressible electrically conducting and heat absorbing fluid past an impulsively moving vertical plate with ramped wall temperature and concentration in a porous medium in the presence of thermal diffusion. The solutions for velocity field, temperature field and concentration distribution are obtained using Laplace transformation technique. The effects of flow parameters such as magnetic parameter (M), Prandtl number (Pr), porosity parameter (Kp), thermal Grashof number (Gr), mass Grashof number (Gc), Schmidt number (Sc), heat absorption parameter (ϕ) and time parameter (t) on the velocity, temperature and concentration distribution of the flow field and the skin friction, heat flux and the rate of mass transfer are studied analytically and presented with the aid of figures and tables. A comparison with earlier study shows that flow separation is caused in case of isothermal plate due to the presence of chemical reacting diffusing species for higher values of Grashof number. Further, the analysis reveals that the Lorentz force opposes the motion of the fluid more effectively in absence of porous matrix and the flow of fluid with higher thermal diffusivity in the presence of porous matrix prevents the back flow.
