A dynamic pressure-sink method for improving large eddy simulation and hybrid Reynolds-averaged Navier–Stokes/large eddy simulation of wall-bounded flows

Abstract

A dynamic method based on introducing pressure sinks at the wall boundary is proposed to improve hybrid Reynolds-averaged Navier–Stokes/large eddy simulation (RANS/LES) and LES on under-resolved meshes of wall-bounded flows. The basic spirit is to enhance the momentum transfer in the boundary layer from the outer layer to the inner layer by introducing a small pressure gradient in the wall-normal direction, so that the skin friction, usually underestimated in hybrid RANS/LES and LES on under-resolved meshes, can recover to the correct level. The dynamic pressure-sink method, applied to LES and hybrid RANS/LES, is first numerically tested in simulating a supersonic flat-plate boundary flow, for which the turbulent inflow condition is treated by the recycling/rescaling approach. The results show obvious improvement as compared to the baseline LES and hybrid RANS/LES results on the same mesh. The method is then applied to LES of a supersonic flow over a compression–expansion ramp, where improved results are also achieved.