Dual solutions in mixed convection flow near a stagnation point on a vertical surface in a porous medium

The steady stagnation point flow through a porous medium bounded by a vertical surface is investigated in this study. The external velocity, which normally impinges the vertical surface and the surface temperature are assumed to vary linearly with the distance from the stagnation point. The governing system of partial differential equations is first transformed into a system of ordinary differential equations, and then they are solved numerically by a finite-difference scheme, namely the Keller-box method. The features of the flow and heat transfer characteristics for different values of the governing parameters are analyzed and discussed. Both cases of assisting and opposing flows are considered. It is found that dual solutions exist for assisting flow, besides that usually reported in the literature for opposing flow. Therefore, the reported results are completely new.