Unsteady Wake of the NASA Common Research Model in Low-Speed Stall

Abstract

Following the completion of the European Strategic Wind Tunnel Improved Research Potential test campaign in the European Transonic Windtunnel, a large amount of data exists for comparison and validation of computational results at high Reynolds numbers. Unsteady simulations were performed using the NASA Common Research Model at a low-speed stall condition. The flowfield is characterized by large scale separation and a highly unsteady wake. An embedded high-resolution hexahedron block in the wake region of the grid has been used to improve resolution of the turbulence in unsteady Reynolds-Averaged Navier–Stokes and delayed detached eddy simulations. Model deformation occurring in the wind tunnel was incorporated into the computational setup. The computational fluid dynamics predictions match the force and wing pressure measurements from the wind tunnel very well. The mean and fluctuation data from the time-resolved particle image velocimetry measurements in the wake is matched by the delayed detached eddy simulations result, with the Reynolds-Averaged Navier–Stokes results showing stronger wake dissipation. Wake characteristics in delayed detached eddy simulations and Reynolds-Averaged Navier–Stokes have been compared using pressure spectra. The validity of the computational models has been evaluated as well.