HEAT AND MASS TRANSFER IN TRANSIENT FLOW BY MIXED CONVECTION BOUNDARY LAYER OVER A STRETCHING SHEET EMBEDDED IN A POROUS MEDIUM WITH CHEMICALLY REACTIVE SPECIES

摘要

An analysis is carried out to study the coupled heat and mass transfer in transient flow by a mixed convection boundary layer past an impermeable vertical stretching sheet embedded in a fluid-saturated porous medium in the presence of a chemical reaction effect. The stretching velocity, the surface temperature, and concentration are assumed to vary linearly with the distance along the surface. The flow is impulsively set into motion rest, and both the temperature and concentration at the surface are also suddenly changed from that of the ambient fluid. The governing partial differential equations are transformed into the self-similar unsteady boundary layer equations and solved by the Runge-Kutta integration scheme with shooting method for the whole transient from initial state (ξ = 0) to final steady state flow (ξ = ∞). Numerical results for the velocity, temperature, and concentration profiles as well as the variation of the local skin friction coefficient, local Nusselt and Sherwood numbers with the Darcy number, buoyancy, and chemical reaction parameters are presented graphically and discussed. This is done to elucidate the influence of the various parameters involved in the problem on the solution.