MHD convection with Soret and Dufour effects in a three-dimensional flow past an infinite vertical porous plate

In this paper, the Soret and Dufour effects on a mixed convective mass transfer flow past an infinite vertical porous plate with transverse sinusoidal suction velocity in presence of a uniform transverse magnetic field have been studied analytically. The magnetic Reynolds number is assumed to be so small that the induced magnetic field can be neglected. The nondimensional equations governing the flow and heat and mass transfer are solved by regular perturbation technique, on the assumption that the solution consists of two parts: a mean part and a perturbed part. The expressions for the velocity, temperature and concentration fields, skin friction at the plate in the direction of the free stream, Nusselt number and Sherwood number at the plate, and the current density are obtained in nondimensional forms. The effects of the Hartmann number M, the Soret number Sr, the Dufour number Du, the Reynolds number Re, Schmidt number Sc, and the Prandtl number Pr on the flow and transport characteristics are discussed through graphs and tables. It is seen that viscous drag on the plate is reduced under the effect of thermal-diffusion (Soret) and diffusion-thermo (Dufour). On the other hand, the rate of heat transfer from the plate to the fluid falls because of the Dufour effect and rises under the Soret effect, whereas the mass flux from the plate to the fluid is delayed under the thermal-diffusion effect, but the reverse occurs under the effect of diffusion-thermo.