High Fidelity CFD Verification Workshop 2024 Test Case: Transonic Turbulent Flow in Sajben Diffuser

To assess the performance of the newly developed one-equation Wray-Agarwal (WA) turbulence model, two test cases of transonic flow in the Sajben diffuser with different outlet pressures are studied. A normal shock appears and induces a flow separation on the diffuser wall due to the shock/boundary layer interaction. The experimental data for both the cases is available, which makes it possible to evaluate the WA model’s capability in predicting the pressure distributions on the diffuser walls. Two well-known models namely the Spalart-Allmaras (SA) one-equation model and the shear stress transport (SST) k-ω model are also employed for comparison. The results indicate that all the three models can predict the pressure distribution but prediction of the shock positions a little shifted towards downstream compared to the experiment. The Wray-Agarwal model shows higher accuracy in the prediction of the shock position and the flow field inside the diffuser. However, it shows relatively poor prediction of the pressure distribution in the flow downstream of the shock for the case with lower outlet pressure.