¹Department of Mathematics, B.R.M. International Institute of Technology, Bhubaneswar-751010 (India)
²Department of Mathematics, College of Engineering Bhubaneswar, Bhubaneswar-751024 (India)
Email:-pkrath_1967@yahoo.in

An unsteady two-dimensional natural convection flow of a visco-elastic (Walters B Model) incompressible, electrically conducting fluid along an infinite hot vertical porous surface with heat source and chemical reaction has been studied. The novelty of the present study is to investigate the effects of fluctuating bounding-surface-temperature as well as presence of a volumetric heat source on the flow and heat transfer phenomena. The governing equations of motion, energy and concentration are solved by successive perturbation technique. The expressions for the skin friction, Nusselt number and Sherwood number are also derived. The variations in the fluid velocity, temperature and concentration are shown graphically whereas numerical values of skinfriction, Nusselt number and Sherwood number are presented in a tabular form for various values of pertinent flow parameters. One of the significant contributions of the present study is that the lapse of time contributes to thickening of velocity boundary layer and thinning of thermal boundary layer and hence contributing to designing of MHD devices controlling fluid flow and heat transfer.