An Evaluation of Low-Reynolds Number k – ε Turbulence Models for Predicting Transition under the Influence of Free-Stream Turbulence and Pressure Gradient

A comparison of ten different low-Reynolds number k – e turbulence models for predicting laminar-turbulent transition is presented. For a realistic evaluation of the models the effect of the k, e initial profiles and the starting location is eliminated by shifting the beginning of the simulation towards a momentum thickness Reynolds number less than 20. In addition the importance of the dissipation length scale at the starting location with respect to an accurate prediction of transit on as well as for the fully turbulent flow regime is demonstrated. The comparison of computational results with experimental data of zero and non-zero pressure gradient flows with and without heat transfer indicates that the model by Lam and Bremhorst and its PTM extension perform best. It is also shown that models involving only the wall paramter y+ in their low-Reynolds number fμ function are not suitable for predicting the laminar and transitional flow regime.