URANS Computations of Shock-Induced Oscillations Over 2D Rigid Airfoils: Influence of Test Section Geometry

The present article deals with recent numerical results from on-going research conducted at ONERA/DMAE regarding the validation of turbulence models for unsteady transonic flows, in which the mechanism of the shock-wave/boundary-layer interaction is important. The main goal is to predict the onset and extent of shock induced oscillations (SIO) that appear over the suction side of two-dimensional rigid airfoils and lead to the formation of unsteady separated areas. Computations are performed with the ONERA object-oriented software "elsA", using the URANS-type approach. In this approach, the unsteady mean turbulent flow is resolved using the standard Reynolds-averaged Navier–Stokes (RANS) equations and closure relationships involving standard transport equation-type models without any explicit modification due to unsteadiness. Applications are provided and discussed for two different test cases, one of which is rather well documented for CFD validation and described by mean-flow, phase-averaged and fluctuating data. Results demonstrate the importance of modelling the upper and lower walls of the test section when trying to capture SIO as precisely as possible with 2D computations, even though the adaptation of wind tunnel walls had been carefully considered. Finally, turbulence validation has been performed using one- and two-transport equation-type models, one of them resulting from in-house investigations for other turbulent flows applications.