Dual solutions of Casson fluid flow over a stretching or shrinking sheet

The stagnation-point flow of an incompressible non-Newtonian Casson fluid over a stretching sheet in the presence of Soret and Dufour effects is investigated. The resulting partial differential equations are reduced to a set of nonlinear ordinary differential equations using similarity transformations and solved using the Matlab bvp4c package. A comparison is made with the results available in the literature and found to be in good agreement. Dual solutions for the velocity, temperature, concentration and skin friction were obtained for some special cases when the stretching parameter is negative. The effect of the Casson parameter on the skin friction, heat transfer and mass transfer rates is discussed.