Effect of Radiation and Gravity Modulation on Unsteady MHD Free Convection Flow Through Porous Medium in Slip-Flow Regime with Entropy

The effect of radiation and periodic oscillation of the gravitational field on free-convection from a vertical plate is investigated. It is assumed that the gravity modulation is given by a harmonic function superimposed on a constant. The permeability and suction velocity is assumed to fluctuate with time. The transformed equations are solved by perturbation technique to investigate the effects of Prandtl number and gravity modulation parameter. The effect of gravity modulation on velocity, temperature, skin friction, penetration distance and entropy are discussed. It is observed that the Prandtl number and gravity modulation affect the shear stress and the rate of heat transfer considerably