Effect of variable viscosity on non-Darcy free or mixed convection flow on a vertical surface in a non-Newtonian fluid saturated porous medium

The effect of variable viscosity on non-Darcy free or mixed convective heat transfer along a vertical surface embedded in a porous medium saturated with a non-Newtonian fluid has been analysed. The viscosity of the fluid is assumed to be an inverse linear function of temperature. Furthermore, the coordinates and dependent variables are transformed to yield computationally efficient numerical solutions which are compared with the existing results, for a few particular cases. The results show that the variable viscosity parameter, viscosity index, mixed convection parameter, Ergun number, Peclet number, Rayleigh number and temperature variation parameter have significant influence on the velocity and heat transfer rate at the surface. (c) 2006 Elsevier Inc. All rights reserved.