The influence of subgrid-scale modelling on the performance of a new non-equilibrium wall-model for large-eddy simulation

Abstract

The computational cost of wall-resolved large-eddy simulations (LES) rapidly becomes prohibitive with increasing Reynolds number. Wall-modelled LES attempts to significantly reduce the computational cost of simulating wall-bounded turbulent flows by modelling the effect of the near-wall small-scale motions, rather than fully or partially resolving them. The present study concentrates on a new wall-model that is able to predict fluctuating wall-shear stress given a large-scale velocity input. The velocity input for the model is affected by the choice of subgrid-scale (SGS) model. Therefore, this study also focusses on the impact of the SGS-model on the distribution of quantities at the wall. Results show that the new wall-model is able to resolve more of the wall shear-stress variance than a standard wall-model; and that the SGS-model affects the distribution of fluctuations of both wall-shear stress and wall-pressure.