Model validation for buoyancy-driven flows inside differentially heated cavities

Convection phenomena induced by body forces have been the subject of extensive research efforts. The reliable computation of buoyant flow is important in a number of engineering sectors, for example, ventilation, cooling of electronic equipments, thermal design of energy storage systems and cooling of nuclear reactors. Here, turbulent natural convection of air in both two dimensional vertical and inclined rectangular cavities are investigated numerically by means of an unstructured finite volume code, Code_Saturne, for an aspect ratio of H/L=28.6 and Rayleigh number of 0.86x106. The two opposing long walls are maintained at uniform and different temperatures. The flow within the cavity is computed using several Reynolds-Averaged-Navier-Stokes (RANS) models, high-Reynolds-number models, such as the Standard κ-ε of Launder (1974), Reynolds Stress models Rij-ε and Rij-ε SSG of Gatski and Speziale (1993) and low-Reynolds-number models, like the ShearStress Transport k-ω SST of Menter (1993) and the υ2 –f model of Durbin (1991) and the new version φ-α model of Billard (2008).The results obtained are compared to two sets of experimental data, Betts and Bokhari (2000) and Esteifi (2009). The cases of vertical and inclined cavity at 60°, under stable stratification, resulted in similar motions, with one recirculation cell over the entire length of the cavity and high turbulence levels within the core. Herethe effectiveness of the above-mentioned RANS models in Code_Saturne, which are also widely used in commercial and research codes, is assessed through comparisons with a range of available experimental data.