Direct numerical simulation of turbulent flow separation from a wall-mounted hump

A high-order-accurate numerical method for solving the incompressible Navier-Stokes equations in general orthogonal coordinates is presented. The method is applied to a test case of the NASA Langley Computational Fluid Dynamics Validation Workshop 2004, a turbulent flow over a wall-mounted hump geometry. Results of direct numerical simulations (DNS) for the unforced flow as well as for a case with steady suction are presented and compared to the available experimental data. The DNS predictions are shown to agree well with the experiments, except in the vicinity of the experimental reattachment locations. The simulations predict slightly longer recirculation regions for both the unforced and the controlled case. The results presented in this work suggest that, with the rapidly increasing computational resources of modern supercomputers such as the Cray XI, DNS is becoming a viable alternative to the use of turbulence models for investigating complex turbulent flows at moderately high Reynolds numbers.