| Popis: |
This study aims at analyzing the modeling of turbulence in a tip-leakage flow. The academic configuration considered is made of a single airfoil and a flat casing, with clearance, at Re=9.3e5. For characterising the turbulence, a zonal large-eddy simulation (ZLES), validated against experimental data, is considered as reference. ZLES was previously shown to describe precisely the flow features in the tip region, including the Reynolds stresses. Two steady Reynolds-averaged Navier-Stokes (RANS) simulations, using Wilcox’s k-ω model, are evaluated against this reference. The first simulation uses the Boussinesq constitutive relation, whereas the second simulation relies on the quadratic constitutive relation (QCR). The analysis focuses on the mean velocities, the Reynolds stresses and a term-to-term decomposition of the turbulent kinetic energy budget. RANS is shown to under-estimate the vorticity of the flow, the Reynolds stresses and the turbulent kinetic energy budget terms. The QCR has little effects on these deficits. |
