Double-diffusive convection in an inclined porous enclosure with opposing temperature and concentration gradients

The problem of unsteady, laminar double-diffusive convective flow of a binary gas mixture in an inclined rectangular enclosure filled with a uniform porous medium is considered. Transverse gradients of heat and mass are applied on two opposing walls of the enclosure while the other two walls are adiabatic and impermeable to mass transfer. A numerical solution based on the finite-difference methodology is obtained. in the absence of the porous medium, an oscillatory flow behavior within the enclosure is predicted for a buoyancy ratio of unity. In the presence of the porous medium, however, a decay in the oscillatory behavior is observed. Representative results illustrating the effects of the inverse Darcy number and the enclosure tilting or inclination angle on the contours of streamline, temperature, concentration and density as well as the profiles of velocity, temperature and concentration at mid section of the enclosure are reported. In addition, results for the average Nusselt and Sherwood numbers are presented and discussed for various parametric conditions. In this study, the thermal and the compositional buoyancy forces are assumed to be opposite. (C) 2001 Editions scientifiques et medicales Elsevier SAS.