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中文核心期刊

可解尺度各向同性湍流的标度律

Scaling law of resolved-scale isotropic turbulence

  • 摘要: 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.

     

    Abstract: In large-eddy simulation (LES), EDQNM theory is employed tocalculate the scaling laws of second- and third-order structure functions,and the skewness of velocity increment, in resolved-scale isotropicturbulence with three different filters, respectively. The scaling law andskewness are affected by several factors, such as the ratio of two-pointdistance to filter size, the LES Reynolds number, and the type of filter.Results show that, when two-point distance is the same magnitude as filtersize, or LES Reynolds number is small, both the scaling law and skewness ofresolved-scale turbulence are far from those of full-scale turbulence andshould be corrected. Three examples of subgrid modeling using these resultsare then introduced.

     

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