Capturing transition and non-transition flows with a new shear stress transport model

Abstract

A new Shear Stress Transport (SST) k-ω model is devised to integrate salient features of both the non-transitional SST k-ω model and correlation-based γ-Reθ transition model. An exceptionally simplified approach is applied to extend the New SST (NSST) model capabilities toward transition/non-transition predictions. Bradshaw’s stress-intensity factor Rb=-uv¯/k can be parameterized with the wall-distance dependent Reynolds numberRey=ky/v; however, as the Rey is replaced by a “flow-structure-adaptive” parameterRμ=vT/v, the resulting Rb is capable of capturing various transition phenomena naturally. The prospective stress-intensity parameter Rb=Rb(Rey,Rμ) is incorporated in the constitutive relations for eddy-viscosity vT and production termPk. The proposed formulation is intrinsically plausible, having a dramatic impact on the prediction of bypass, separation-induced and natural transitions together with non-transitional flows. An extra viscous-production term Pklim is added with the k-equation to ensure proper generation of k at the viscous sublayer when computing separation-induced transition over a Low-Reynolds Number (LRN) airfoil. Results demonstrate that the NSST k-ω model maintains an excellent consistency with both SST k-ω and γ-Reθ models.