ASSESSMENT OF TURBULENCE MODELS FOR NATURAL-CONVECTION IN AN ENCLOSURE

Two available low-Reynolds number k-epsilon turbulence models have bee n used to predict turbulent natural convection within a differentially heated enclosure for the purpose of assessing their relative merits. Tn one model, fixed numerical values are employed for the model coeffi cients; in the other model, the coefficients vary with the value of th e local turbulence Reynolds number. The numerical results from both mo dels are compared to published experimental data. In general, the vari able coefficient model predicts lower turbulence levels than the fixed coefficient model. Both models predict measured velocity profiles ade quately, but overall, the predictions of the variable coefficient mode l are superior. Tile average Nusselt numbers are predicted more accura tely by the variable coefficient model than by the fixed coefficient m odel.