Evaluation of Detached Eddy Simulation for Turbulent Wake Applications

Simulations of a low-speed square cylinder wake and a supersonic axisymmetric base wake are performed using the detached eddy simulation model. A reduced-dissipation form of a shock-capturing flux scheme is employed to mitigate the effects of dissipative error in regions of smooth flow.The reduced-dissipation scheme is demonstrated on a two-dimensional square cylinder wake problem, showing a marked improvement in accuracy for a given grid resolution. The results for simulations on three grids of increasing resolution for the three-dimensional square cylinder wake are compared with experimental data and to other computational studies. The comparisons of mean flow and global flow quantities to experimental data are favorable, whereas the results for second order statistics in the wake are mixed and do not always improve with increasing spatial resolution. Comparisons to large eddy simulation are also generally favorable, suggesting detached eddy simulation provides an adequate subgrid scale model. Predictions of base drag and centerline wake velocity for the supersonic wake are also good, given sufficient grid refinement. These cases add to the validation library for detached eddy simulation and support its use as an engineering analysis tool for accurate prediction of global flow quantities and mean flow properties. Nomenclature A = cylinder aspect ratio CDES = detached eddy simulation model constant Cd = drag coefficient Cl = lift coefficient Cpb = base pressure coefficient D = square cylinder width d = distance to wall Fj = inviscid flux vector lR = wake recirculation length M = Mach number N = number of grid cells p = pressure Qlj = flux limiter R = axisymmetric base radius Rj = matrix of right eigenvectors Re = Reynolds number r = radial coordinate