Three-Dimensional Double-Diffusive Natural Convection with Opposing Buoyancy Effects in Porous Enclosure by Boundary Element Method

A three-dimensional double-diffusive natural convection with opposing buoyancy effects in a cubic enclosure filled with fluid saturated porous media is studied numerically using the boundary element method (BEM). The mathematical model is based on the space-averaged Navier–Stokes equations, which are coupled with the energy and species equations. The simulation of coupled laminar viscous flow, heat and solute transfer is performed using a combination of single-domain BEM and subdomain BEM, which solves the velocity-vorticity formulation of governing equations. The numerical simulations for a case of negative values of buoyancy coefficient are presented, focusing on the situations where the flow field becomes three-dimensional. The results are analyzed in terms of the average heat and mass transfer at the walls of the enclosure. When possible, the results are compared with previous existing numerical data published in literature.