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 ...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.展开更多
基金Project supported by the National Natural Science Foundation of China(No.11490551)the Fundamental Research Funds for the Central Universities(Nos.lzujbky-2016-k13 and lzujbky-2018-k07)
文摘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.
