Heat and mass transfer in composite fluid-porous layer: Effect of permeability

Numerical simulations are conducted for two-dimensional, steady state, double diffusive flow in a composite fluid-porous layer. Both the temperature and solute gradients are imposed horizontally, and the two buoyancy effects can either augment or counteract each other. The porous medium is modeled according to the Darcy-Brinkman and Forchheimer model, and the SIMPLER algorithm, based on the finite volume approach, is used to solve the pressure-velocity coupling, An extensive series of numerical simulations is conducted in the range: 10(3) less than or equal to Gr less than or equal to 10(6), 10(-8) less than or equal to Da less than or equal to 1, -20 less than or equal to N less than or equal to 20, and 1 less than or equal to Le less than or equal to 10(2). It is shown that the main effect of the presence of the porous layer is to reduce the heat and mass transfer when the permeability is reduced. With appropriate combination of Grashof number, Lewis number, and the buoyancy ratio, multiple cell flow patterns are illustrated.