Wall-resolved and wall-modeled ILES based on high-order DG

Abstract

In wall-modeled large eddy simulations (WM-LES) based on wall-stress-models, flow scales are resolved in the outer boundary layer and modeled in the inner layer. In order to avoid the so-called "log-layer mismatch", we take the thickness h_wm of the wall-modeled layer not to be the typically used frist grid layer thickness, but we take it independent of the grid as 20% of the boundary layer thickness. Important input to the wall-shear-stress approach is the near-wall velocity profile for which various approximations exist. In this work, we compare the results of the wall-shear-stress approach with the near-wall velocity profile given by Reichardt's law to the results of the wall-shear-stress approach where the near-wall velocity profile is given by DNS data. The WM-LES approach is implemented in the context of implicit large eddy simulations (ILES) based on high-order Discontinuous Galerkin methods. Numerical results are shown for the periodic channel flow. Comparisons are given for wall-modeled ILES to ILES (without wall-model) as well as to DNS data.