Aiding and opposing mechanisms of mixed convection in a shear- and buoyancy-driven cavity

The present study was conducted to numerically investigate the transport me chanism of laminar combined convection in a shear- and buoyancy-driven cavi ty. The focus was on the interaction, of the forced convection induced by t he moving wall with the natural convection induced by the buoyancy. Two ori entations of thermal boundary conditions at the cavity walls are considered in order to simulate the aiding and opposing buoyancy mechanisms. Velocity and temperature distributions of the fl;ow are carried out through a strea m function-vorticity transformation with a finite difference scheme. Parame tric studies of the effect of the mixed convection parameter, Gr/Re-2, on t he fluid flow and heat transfer have been performed. Calculations cover Re= 100, Pr=0.71 and Gr/Re-2 the range of 0.01-100. Three different regimes are observed with increasing Gr/Re-2: Forced convection (with negligible natur al convection), mixed convection (comparable forced and natural convection) and natural convection (with negligible forced convection). The code devel oped was carefully tested for the two limiting cases, the pure forced conve ction and the pure natural convection, for which experimental and numerical data are available. (C) 1999 Elsevier Science Ltd.