Examination of the shear stress transport assumption with a low-Reynolds number κ - ω model

Paper in proceeding, 2007

Using a low-Reynolds number k - ω model and its high-Reynolds number variant as base models, the Shear Stress Transport (SST) concept is examined in computations of flows around the RAE2822 airfoil and the DLR-F6 wind-body configuration. Both flows are characterized by local boundary layer separation. Based on an analysis of the net production for the turbulent kinetic energy, k, and for its specific dissipation rate, u, the rationale is highlighted behind the SST formulation that enables improved predictions of flow separation. It is shown that the SST formulation may make the modeling contain the growth of the production of k and, consequently, suppress the turbulent diffusion. Incorporating the SST assumption, the model responds more appropriately to the effect of an adverse pressure gradient in the boundary layer and produces more extended flow separation bubble than the original base model. Improvement due to the SST formulation is also observed in predictions of the shock location for the transonic aerodynamic flows considered in this work.