APPLICATION OF TURBULENCE MODELS TO BYPASS TRANSITION

The present study considers the use of low-Reynolds number, single-poi nt closures for transition prediction at high levels of free-stream tu rbulence. The work is focused on two differential Reynolds Stress Tran sport models, which are compared with the k - epsilon model of Launder and Sharma. Calculations are carried our for attached boundary layer flow on a flat plate equipped with a sharp lending edge at zero-pressu re gradient and for various free-stream turbulence levels. Comparisons with results from a large eddy simulation reveal significant shortcom ings in the modeling of the dissipation, with a large overprediction i n the pretransitional boundary layer. The present results are in some cases in conflict with other results reported in the literature, and i t is shown that the discrepancies can be ascribed to the implementatio n of the free-stream boundary conditions.