Application of the Nonlinear SST Turbulence Model for Simulation of Anisotropic Flows

Abstract

The application of the nonlinear SST turbulence model (SST NL) for the calculation of flows with turbulence anisotropy is considered. The results of the following validation test cases are presented: the flow in a square duct, the corner flow separation at a wing-body junction (NASA Juncture Flow) and the transonic wing flow (NASA CRM). The nonlinear model has been found to significantly improve the quality of simulating the anisotropic flows as compared to models based on the Boussinesq hypothesis. It is shown that the model prevents false corner separation at the wing-body junction and thereby achieves a qualitative improvement in simulation results. The test case of the transonic wing flow revealed an upstream displacement of the shock wave on the upper side of the wing which leads to an underestimation of the lift force when using the SST NL model. In all the tests considered, the SST NL model required an increase in computational cost of at most 5 % compared to the conventional SST model.