Large Eddy Simulation of Turbulent Channel Flow with 3D Roughness Using a Roughness Element Model  

作　　者：杨帆 张会强 陈昌麒 王希麟 

机构地区：[1]Department of Engineering Mechanics, Tsinghua University, Beijing 100084 [2]Department of Applied Mathematics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong

出　　处：《Chinese Physics Letters》2008年第1期191-194,共4页中国物理快报（英文版）

基　　金：Supported by the National Natural Science Foundation of China under Grant No 50576046, and the AMSS-PolyU Joint Research Institute for Engineering and Management Mathematics of The Hong Kong Polytechnic University under Grant No 1-BA05.

摘　　要：Large eddy simulation of turbulent channel flow with dense and small 3D roughness elements is carried out using a roughness element model Profiles of mean Reynolds stress, mean velocity and rms velocity as well as turbulent structures near the wall are obtained. The shear stress in the rough wall is larger than that in the smooth wall side and the rough wall has a larger influence on the channel flow. Profiles of mean streamwise velocity near the wall have logarithmic velocity distributions for both smooth and roughness walls, while there is a velocity decrease for the rough wall due to larger fractional drag. All the three components of rms velocities in the rough wall region are larger than that in the smooth wall region, and the roughness elements on the wall increase turbulent intensity in all directions. The s^reak spacing and average diameter of near wall quasi-s^reamwise vortices increase with the presence of roughness elements on the wall and it is shown that the rough wall induces complex and strong streamwise vortices. Results of dense and small 3D roughness elements in both turbulent statistics and structure, obtained with a relatively simple method, are found to be comparable to related experiments.Large eddy simulation of turbulent channel flow with dense and small 3D roughness elements is carried out using a roughness element model Profiles of mean Reynolds stress, mean velocity and rms velocity as well as turbulent structures near the wall are obtained. The shear stress in the rough wall is larger than that in the smooth wall side and the rough wall has a larger influence on the channel flow. Profiles of mean streamwise velocity near the wall have logarithmic velocity distributions for both smooth and roughness walls, while there is a velocity decrease for the rough wall due to larger fractional drag. All the three components of rms velocities in the rough wall region are larger than that in the smooth wall region, and the roughness elements on the wall increase turbulent intensity in all directions. The s^reak spacing and average diameter of near wall quasi-s^reamwise vortices increase with the presence of roughness elements on the wall and it is shown that the rough wall induces complex and strong streamwise vortices. Results of dense and small 3D roughness elements in both turbulent statistics and structure, obtained with a relatively simple method, are found to be comparable to related experiments.

关 键 词：BOUNDARY-LAYERS WALL 

分 类 号：O357.5[理学—流体力学]