Unsteady natural convection heat transfer within a porous square enclosure with insulated rectangular obstacles on the top and bottom walls

Numerical investigation of unsteady natural convection heattransfer in a porous square enclosure with insulatedrectangular obstacles on horizontal walls has beenperformed. The fluid inside the enclosure considered is air,two horizontal walls are adiabatic while the left wall is hotand the right wall is maintained at cold temperature. Thegoverning equations are written based on Darcy’s law andthen solved numerically using finite volume method withFLUENT software. The Boussinesq approximation isemployed for the fluid properties and density change isrelated to temperature change which in this way thetemperature field is coupled to the flow field. The secondorder upwind scheme is used to discretize the convectiveand diffusive terms and SIMPLE solution algorithm isutilized to couple the pressure and velocity. The resultsshow that obstacle height change and it’s number lead tomore reduction of average Nusselt number thandisplacement of obstacle.