论文标题
湍流速度增量的不对称性
Asymmetry of velocity increments in turbulence
论文作者
论文摘要
我们使用良好的高雷诺数湍流的直接数值模拟来研究湍流的基本统计特性 - 速度增量的不对称性 - 可能对重要动力学有影响。现有的小规模现象学模型忽略了这种特性，在速度增量力矩（或结构函数）的非单调趋势中最为突出，并且具有力矩顺序，并且在给定的分离距离的普通结构和绝对结构函数之间存在差异。我们表明，高阶结构函数几乎完全来自速度增量概率密度的负面，从本质上消除了普通和绝对矩之间的歧义，并提供了对此结果的合理的动力学解释。
We use well-resolved direct numerical simulations of high-Reynolds-number turbulence to study a fundamental statistical property of turbulence -- the asymmetry of velocity increments -- with likely implications on important dynamics. This property, ignored by existing small-scale phenomenological models, manifests most prominently in the non-monotonic trend of velocity increment moments (or structure functions) with the moment order, and in differences between ordinary and absolute structure functions for a given separation distance. We show that high-order structure functions arise nearly entirely from the negative side of the probability density of velocity increments, essentially removing the ambiguity between ordinary and absolute moments, and provide a plausible dynamical interpretation of this result.
