速度估计模型在大涡模拟中的应用

介绍了速度估计模型的基本思想及其在物理空间的实现。速度估计模型依靠湍流大尺度的非线性作用估计出小尺度,从而可直接求解亚格子应力项而不需要额外的模型。本文采用该模型对不同雷诺数下的各向同性衰减湍流进行了模拟,并与直接数值模拟、理论分析和其他亚格子模型的大涡模拟结果进行了比较。也初步考察了网格分辨率、不同精度的紧致格式对大涡模拟结果的影响。

Velocity estimation model for Large Eddy Simulation

The basic idea of velocity estimation model(VEM) and its implementation in physical space are introduced.VEM uses the information contained in the nonlinear term of large scales to estimate the small scales.The subgrid stress tensor can be calculated directly without any SGS model.The simulation of isotropic decaying turbulence at different low and high Reynolds number is used to verify this model,by comparing the results with theoretical analysis,Direct Numerical Simulation and other Large Eddy Simulation models.VEM obtained very good results in all the simulations done in this paper.The influence of grid resolutions is also investigated.In order to extend VEM to complex geometry,the compact difference schemes are adopted instead of the conventional spectral method.The effect of the order of these schemes on the simulation result is discussed.