Abstract

The unsteady boundary layer flow over a porous stretching surface embedded in a porous medium in the presence of heat source or sink is studied. The unsteadiness in the flow and temperature fields is caused by the time dependence of the stretching velocity and the surface heat flux. The governing partial differential equations are transformed into a system of ordinary differential equations, which is then solved numerically by applying shooting method using Runge-Kutta method. The solution is found to be dependent on the governing parameters including the Prandtl number, porous parameter, heat source /sink parameter, suction or injection parameter and unsteadiness parameter. Comparison of numerical results is made with previously published results under the special cases, and found to be in good agreement. Effects of the Prandtl number, porous parameter, heat source /sink parameter, suction or injection parameter and unsteadiness parameter on the flow and heat transfer are examined.

Key words: Unsteady flow, boundary layer flow, stretching surface, heat transfer, porous medium and source /sink, suction or injection.