MIXED CONVECTION DUE TO A FINITE HORIZONTAL FLAT-PLATE EMBEDDED IN A POROUS-MEDIUM

Simultaneous steady forced and free convective flow past a heated or c ooled body in a semi-infinite porous medium subject to the Darcy-Bouss inesq approximation is treated analytically and numerically. A correct ion term is derived in terms of the Rayleigh (Ra) and Peclet (Pe) numb ers for the velocity and temperature fields far from the body; this is subsequently implemented in a numerical treatment, using finite-diffe rence techniques in elliptical coordinates, for 1 less than or equal t o Pe less than or equal to 100 and \Ra\ less than or equal to 10(3). F low separation is observed for both heating and cooling, perhaps surpr isingly so for the former case since the flow near the plate is being accelerated by comparison with the forced convection case. A simple an alogy with inviscid flow theory serves to illustrate the manner in whi ch separation eddies are formed for both heating and cooling cases.