A study of turbulence and transition models in a flow solver for turbomachines

Abstract

This chapter explores turbulence and transition models in a flow solver for turbomachines. It also focuses on the prediction of transitional boundary layers in typical turbomachinery flows. It is noted that the computations with two different low Reynolds number turbulence models are performed two-dimensionally as well as quasi-three-dimensionally, using an implicit Navier-Stokes flow solver. Furthermore, additional algebraic transition models are applied to improve the accuracy of prediction. The two different test cases chosen include a linear transonic compressor cascade and linear low pressure turbine cascade. A laminar separation bubble can be observed on the suction side of the blades of the turbine cascade whereas a shock-induced separation can be found on the suction side of the blades of the compressor cascade. Computational results thus obtained are compared with the experiments, and the effect of transition modeling is analyzed. It is observed that the prediction of the boundary-layer development can be improved and compared to fully turbulent computations when algebraic transition models are applied.