COMPUTATIONAL ANALYSIS OF COUPLED RADIATION-CONVECTION DISSIPATIVE NON-GRAY GAS-FLOW IN A NON-DARCY POROUS-MEDIUM USING THE KELLER-BOX IMPLICIT DIFFERENCE SCHEME

The effects of thermal radiation parameter (F), transpiration (gamma), Eckert number (Ec), Prandtl number (Pr), buoyancy (Grashof number Gr) , a Darcy parameter (Re/Gr Da) and a Forcheimmer inertial parameter (F s Re-2/Gr Da) on two-dimensional free convective flow of an optically thin, near-equilibrium, non-gray gas past a vertical surface in a non- Darcy porous medium, are studied using the robust Keller finite-differ ence technique incorporating Newtonian quasilinearization and block-tr idiagonal elimination. The Darcy-Brinkman-Forcheimmer inertial-viscous flow model is used for the momentum equation and the Cogley-Vincenti- Giles formulation is adopted to simulate the radiation component of he at transfer. The one-dimensional thermal radiation model works success fully for gases in the optically thin limit. Pseudo-similarity transfo rmations are employed to simplify the highly non-linear partial differ ential equations for momentum and heat transfer into numerically manag eable pseudosimilar ordinary differential equations which are solved w ith Keller's box method, Effectively, the radiation contribution is se en to take the form of a linear temperature term F theta coupled with the streamwise pseudo-similar variable xi. Local wall shear stress and local heat transfer rates are systematically computed for a wide sele ction of radiation parameter F values. The results are presented graph ically for different gases. (C) 1998 John Wiley & Sons, Ltd.