Application of Crossflow Transition Criteria to Local Correlation-Based Transition Model

There exist many approaches for the prediction of laminar-turbulent transition. For general and turbomachinery flows, a combination of the Shear Stress Transport (SST) turbulence model by Menter and the γ-Re

_Θ transition model by Langtry and Menter is widely spread. This transition model is developed and validated for several generic and turbomachinery testcases but fails for transition prediction in three-dimensional flows, like cross flow instabilities induced transition on swept wings or the laminar-turbulent transition process on the sidewalls of low-pressure turbine cascades. For this purpose the γRe

_Θ model is extended with an indicator function after Menter and Smirnov to account for boundary layer transition in three-dimensional flows. The model was validated on two infinite swept wing test cases, where the Reynolds number and the sweep angle were varied, respectively. An additional swept wing test case with discontinuously increasing wing sweep was investigated as well as an 1:6 spheroid. An adequate match to experimental data was achieved in all general testcases. For the purpose of turbomachinery flow the well known Durham cascade was taken into account. Within this testcase the capability of the model with regard to boundary layer transition on the sidewalls of this testcase will be shown.For comparison, all testcases are also investigated with the standard γ-Re

_θ model and an extinction of the γ-Re

_Θ model to cross flow induced transition according to Müller and Herbst.