Thermal-diffusion and diffusion-thermo effects on convective heat and mass transfer in a visco-elastic fluid flow through a porous medium over a stretching sheet

An analysis has been carried out to obtain the thermal-diffusion and diffusion-thermo effects on the mixed free forced convective and mass transfer in a visco-elastic fluid flow through a porous medium over a stretching sheet. Here, the driving force for the flow is provided by an impermeable sheet stretched with a velocity proportional to the distance from a slit and buoyancy effects due to both temperature and concentration gradient. The partial differential equations governing the problem under consideration have been transformed by a similarity transformation into a system of ordinary differential equations which are solved numerically by applying the shooting method. The effects of Soret number, Dufour number, visco-elastic parameter, Porosity parameter, Grashof number and modified Grashof number on the velocity, temperature and concentration have been discussed. Numerical results for the problem considered are given and illustrated graphically. Copyright (C) 2006 John Wiley & Sons, Ltd.