针对大涡模拟,首先利用EDQNM能谱和传输谱理论,在3种不同的过滤器下分别计算可解尺度各向同性湍流的二阶、三阶结构函数标度律,并通过速度差扭率验证了可解尺度湍流的ESS理论.研究了该可解尺度湍流标度律及速度差扭率与多个因素的关系,这些因素包括:两点距离与过滤尺度的比、大涡模拟雷诺数和过滤器类型.结果显示,当两点距离位于过滤尺度量级时或大涡模拟雷诺数较小时,可解尺度标度律与未过 滤流场的标度律相差很大进而必须加以修正,而且可解尺度流场也不再总是满足ESS理论进而对应的速度差扭率也需要修正.然后通过3个例子介绍了这些结果在大涡模拟亚格子模型中的应用.%In large-eddy simulation (LES), EDQNM theory is employed to calculate the scaling laws of second- and third-order structure functions, and the skewness of velocity increment, in resolved-scale isotropic turbulence with three different filters, respectively.The scaling law and skewness are affected by several factors,such as the ratio of two-point distance to filter size, the LES Reynolds number, and the type of filter.Results show that, when two-point distance is the same magnitude as filter size, or LES Reynolds number is small, both the scaling law and skewness of resolved-scale turbulence are far from those of full-scale turbulence and should be corrected.Three examples of subgrid modeling using these results are then introduced.
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