Large eddy simulation of high-Reynolds-number atmospheric boundary layer flow with improved near-wall correction

Abstract

It is highly attractive to develop an efficient and flexible large eddy simulation (LES) technique for high-Reynolds-number atmospheric boundary layer (ABL) simulation using the low-order numerical scheme on a relatively coarse grid, that could reproduce the logarithmic profile of the mean velocity and some key features of large-scale coherent structures in the outer layer. In this study, an improved near-wall correction scheme for the vertical gradient of the resolved streamwise velocity in the strain-rate tensor is proposed to calculate the eddy viscosity coefficient in the subgrid-scale (SGS) model. The LES code is realized with a second-order finite-difference scheme, the scale-dependent dynamic SGS stress model, the equilibrium wall stress model, and the proposed correction scheme. Very-high-Reynolds-number ABL flow simulation under the neutral stratification condition is conducted to assess the performance of the method in predicting the mean and fluctuating characteristics of the rough-wall turbulence. It is found that the logarithmic profile of the mean streamwise velocity and some key features of large-scale coherent structures can be reasonably predicted by adopting the proposed correction method and the low-order numerical scheme.