A stochastic representation of the local structure of turbulence
A stochastic representation of the local structure of turbulence
复制标题
湍流局部结构的随机表示
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
Vincent Vargas
中科院分区：
文献类型：
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作者：
L. Chevillard;Raoul Robert;Vincent Vargas
基于短时欧拉方程的力学原理，我们证明了涡度场的近期流体变形（RFD）闭包，忽略了流体粒子平流的早期阶段，允许建立一个与经验湍流共享许多属性的 3D 不可压缩速度场，例如 RQ 平面的泪滴形状。不幸的是，非高斯性很弱（即，没有间歇性），并且涡量优先与变形的错误特征向量对齐。然后，我们证明，稍微修改以前的矢量场以施加湍流的长程相关性质，可以重现稳态流的主要属性。这样做，我们最终得到了一个真实的不可压缩、倾斜和间歇的速度场，它再现了惯性范围内 3D 湍流的主要特征，包括正确的涡度对齐属性。
Based on the mechanics of the Euler equation at short time, we show that a Recent-Fluid-Deformation (RFD) closure for the vorticity field, neglecting the early stage of advection of fluid particles, allows to build a 3D incompressible velocity field that shares many properties with empirical turbulence, such as the teardrop shape of the RQ-plane. Unfortunately, non-Gaussianity is weak (i.e., no intermittency) and vorticity gets preferentially aligned with the wrong eigenvector of the deformation. We then show that slightly modifying the former vectorial field in order to impose the long-range–correlated nature of turbulence allows to reproduce the main properties of stationary flows. Doing so, we end up with a realistic incompressible, skewed and intermittent velocity field that reproduces the main characteristics of 3D turbulence in the inertial range, including correct vorticity alignment properties.