Simulations of Complex Turbulent Flows with RANS-LES Hybrid Approaches

Two advanced DES (detached eddy simulation) methods, delayed-DES (DDES) and improved-delayed DES (IDDES), are the two wide-used RANS-LES (Reynolds averaged Navier-Stokes and large eddy simulation) hybrid methods. They are applied to accurately simulate the unsteady complex turbulent flows at high Reynolds numbers with a wide Mach number range from low speed to hypersonic. In addition, the dissipation properties of the spatial scheme are also discussed and the adaptive dissipation scheme performs well. After comparing the performance of DDES and IDDES, IDDES is recommended for the following simulations: massive separation flows past tandem cylinders and rudimentary landing gear at low speed, cavity flow at transonic, supersonic and hypersonic conditions. The pressure fluctuations and dynamic loads are accurately captured near the wall.