Preservation of statistical properties in large-eddy simulation of shear turbulence
Preservation of statistical properties in large-eddy simulation of shear turbulence
复制标题
剪切湍流大涡模拟中统计特性的保留
DOI：
10.1017/s0022112007008609
复制
发表时间：
2007
影响因子：
3.7
通讯作者：
R. Piva
中科院分区：
文献类型：
--
作者：
P. Gualtieri;C. Casciola;R. Benzi;R. Piva
我们讨论了如何正确地使用大涡模拟（LES）来预测剪切湍流中分辨速度波动的统计数据。为了这个目的，一个后验比较LES数据对过滤直接数值模拟（DNS）是用来建立必要的条件，过滤器规模LF必须满足，以实现保存的统计特性的解决领域。在这种情况下，通过利用剪切尺度LS的物理作用，卡门-豪沃思方程允许评估LES数据的规模按规模的能量生产，能量转移和次网格能量通量。即使高阶统计特性的解决尺度，如纵向速度增量的概率密度函数被很好地再现，提供了相对于剪切尺度的过滤器尺度的相对位置被适当地选择。在这里，我们认为均匀剪切流作为最简单的非平凡流，它完全保留了典型的任何剪切流的湍流动能生产的基本机制，其优点是，空间均匀性意味着一个明确定义的值的剪切尺度，而在近壁区域的分辨率要求相关的数值困难被避免。
We discuss how large-eddy simulation (LES) can be properly employed to predict the statistics of the resolved velocity fluctuations in shear turbulence. To this purpose an a posteriori comparison of LES data against filtered direct numerical simulation (DNS) is used to establish the necessary conditions that the filter scale LF must satisfy to achieve the preservation of the statistical properties of the resolved field. In this context, by exploiting the physical role of the shear scale LS, the Kármán–Howarth equation allows for the assessment of LES data in terms of scale-by-scale energy production, energy transfer and subgrid energy fluxes. Even higher-order statistical properties of the resolved scales such as the probability density function of longitudinal velocity increments are well reproduced, provided the relative position of the filter scale with respect to the shear scale is properly selected. We consider here the homogeneous shear flow as the simplest non-trivial flow which fully retains the basic mechanism of turbulent kinetic energy production typical of any shear flow, with the advantage that spatial homogeneity implies a well-defined value of the shear scale while numerical difficulties related to resolution requirements in the near wall region are avoided.