Local similarity solutions for unsteady MHD free convection and mass transfer flow past an impulsively started vertical porous plate with Dufour and Soret effects

An unsteady free convection and mass transfer flow of an electrically conducting, viscous, incompressible fluid, past an infinite vertical porous plate in the presence of a transverse magnetic field is studied, when the plate is moved impulsively with a constant velocity in the direction of the flow. Both the Dufour and Soret effects are considered for a hydrogen-air mixture as the nonchemically reacting fluid pair. The nonlinear 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 using the Nachtsheim-Swigert shooting iteration technique together with a sixth order Runge-Kutta integration scheme. The resulting velocity. temperature and concentration distributions are shown graphically for different values of the parameters entering into the problem. Finally, the numerical values of the local skin-friction coefficient, local Nusselt number and local Sherwood number are also presented in a tabular form.