Unsteady mixed convection over an exponentially stretching surface: Influence of Darcy-Forchheimer porous medium and cross diffusion

This paper deals with the unsteady double-diffusive mixed convection flow over an exponentially permeable vertical stretching surface in the presence of Darcy-Forchheimer, Dufour, and Soret (cross diffusion) effects. The unsteadiness in the flow, temperature, and the species concentration fields are due to a time-dependent free stream velocity as well as an exponentially stretching surface velocity. The boundary layer equations are transformed into nondimensional form and solved numerically using an efficient, implicit finite difference scheme in combination with the quasilinearization technique for various governing physical parameters. Numerical computations are displayed graphically to illustrate the Soret, Dufour, and permeability effects on the velocity, temperature, and species concentration profiles. Numerical results for the skin friction coefficient, heat transfer, and mass transfer rates are also presented. The present results are compared with previously published work and are found to be in excellent agreement.