Direct numerical simulation of a separated turbulent boundary layer over a bump*

The separated turbulent boundary layer over a Gaussian bump is computed by direct numerical simulation (DNS) of the incompressible Navier-Stokes equations. The smooth, two-dimensional bump causes a rapid succession of strong favorable-to-adverse pressure gradients, resulting in a separation bubble on the downstream side. At the start of the bump, the Reynolds number based on the momentum thickness is 3,200, and the boundary layer thickness is of the order of the bump height. Results from preliminary DNS simulations are discussed, assessing the effects of the inflow, outflow and far-field boundary conditions. Future data from this study will be used for the purposes of data driven turbulence modeling.