A central-moments-based lattice Boltzmann model for large-eddy simulation of neutrally-stratified turbulent flows is described. Through comparative simulations of the airflow within and above a homogeneous plant canopy, the performance of the model is evaluated with respect to a conventional large-eddy-simulation model based on the incompressible Navier–Stokes equations. Simulated turbulence statistics, such as the mean velocity, velocity variances, velocity skewness, and power spectra, are shown to be almost identical between the two models. The spatial structure of coherent eddies and their maintenance processes are also confirmed to be properly represented by the lattice Boltzmann method through analysis of the turbulence kinetic energy budget and spatial two-point correlation functions. Using the simulated results, the energetics of the streamwise-elongated streaky structures commonly observed over vegetation and urban canopies are examined. While the short-wavelength components of the shear-generated streamwise kinetic energy are redirected rapidly by pressure to the lateral and vertical velocity components, long-wavelength energy tends to remain in the streamwise velocity component, which is dissipated in relatively slower processes. Consequently, the streaky structures persist in the streamwise velocity component.

中文翻译：

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使用基于中心矩的格子 Boltzmann 方法对植物冠层内和上方的中性分层湍流进行大涡模拟

描述了一种基于中心矩的格子 Boltzmann 模型，用于中性分层湍流的大涡模拟。通过对均质植物冠层内部和上方的气流进行比较模拟，相对于基于不可压缩 Navier-Stokes 方程的传统大涡流模拟模型评估模型的性能。两种模型的模拟湍流统计数据（例如平均速度、速度方差、速度偏度和功率谱）几乎相同。通过对湍流动能收支和空间两点相关函数的分析，也证实了相干涡旋的空间结构及其维持过程可以用格子玻尔兹曼方法正确表示。使用模拟结果，检查了通常在植被和城市檐篷上观察到的流向细长条纹结构的能量学。虽然剪切产生的流向动能的短波长分量被压力迅速重定向到横向和垂直速度分量，但长波长能量倾向于保留在流向速度分量中，并在相对较慢的过程中消散。因此，条纹结构在流向速度分量中持续存在。它在相对较慢的过程中消散。因此，条纹结构在流向速度分量中持续存在。它在相对较慢的过程中消散。因此，条纹结构在流向速度分量中持续存在。