旋转槽道湍流的格子Boltzmann方法模拟

基于多松弛格子Boltzmann方法的大涡模拟对雷诺数为194,旋转数从0~5.0的旋转槽道湍流进行数值模拟.采用动态亚格子应力模型模化滤波后的不封闭项,修正二阶矩作用力模型计算压力梯度、哥氏力.对平均速度、均方根脉动速度、雷诺应力以及湍流结构进行了计算.结果显示哥氏力使流场平均速度呈现不对称性:在压力面,随着旋转数的增加,湍流度增强;而在吸力面湍流脉动减弱,具有层流化的趋势.将格子Boltzmann模型与直接数值模拟求解进行对比,结果验证了格子Boltzmann方法在旋转湍流模拟中的可行性. 

Lattice Boltzmann simulations of rotating channel turbulent flow

The large eddy simulation based on the multiple relaxation time lattice Boltzmann method (LBM) was used to simulate the fully developed turbulent flow in a rotating channel at Reynolds number equaling to 194. The rotation number varied from 0 to 5.0 based on the friction velocity. The dynamic subgrid stress model was performed to model the non-closure term after filtering; the modified second moment force model was used to compute the pressure gradient and the Coriolis force. The statistical quantities such as: mean velocity, root mean square velocity fluctuations, Reynolds stress and the turbulence structure were calculated to elucidate the effect of Coriolis force on turbulent flow. The result shows that the profile of the average streamwise velocity becomes asymmetric and the turbulence intensity increases on the pressure side, while on the suction side the flow has a tendency to become laminar. The comparison results between the direct numerical simulation and present work show that the ability of LBM to simulate rotating turbulence is confirmed.