Modelling a boundary layer flow over a horizontal surface embedded in porous media with cross diffusion effects

A boundary layer flow over a horizontal surface embedded in porous media with cross diffusion effects has been investigated. The dimensionless governing partial differential equation was transformed into a system of ordinary differential equations using the standard similarity techniques. The transformed system of differential equations was solved using the fourth order Runge-Kutta method combined with a shooting technique. The effect of various flow parameters involved on dimensionless velocity, temperature and concentration in the boundary layer have been presented and displayed graphically. The skin friction coefficient, the heat transfer and mass transfer rates at the wall have been also determined numerically and presented in tabular forms for different values of the parameter involved in the flow. The results show that within the boundary layer, the effect of varying the Dufour number on the temperature distribution is very significant. Increasing the Dufour number results in the rapid increase in the thermal boundary layer thickness and increases the rates of heat and mass transfer at the surface. Increasing the Soret number increases the concentration profile thickness and decreases the rates of mass transfer at the surface. Increasing the buoyancy parameters accelerates the fluid velocity such that the velocity increases rapidly exceeding the free stream velocity and appear to have a maximum value and the rates of both heat and mass transfers at the surface are increased. Cross diffusion includes Dufour and Soret effects, therefore in this study it is observed that cross diffusion effect increases flow properties.