Intermittent vortex structures in homogeneous isotropic turbulence
Intermittent vortex structures in homogeneous isotropic turbulence
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DOI：
10.1038/344226a0
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发表时间：
1990-03
期刊：
影响因子：
64.8
通讯作者：
Z. She;Eric Jackson;S. Orszag
中科院分区：
文献类型：
--
作者：
Z. She;Eric Jackson;S. Orszag
尽管发展良好的湍流表现出复杂的、混乱的空间和时间行为，但有许多实验证据表明，也存在显著程度的相干性。小尺度湍流运动中的相关性与大的随机相互作用系统中通常期望的高斯统计有很大的偏差。这种现象，被称为不稳定性，长期以来一直抵制分析描述，因为缺乏一个简单的，通用的表征湍流结构3。在这里，我们报告的数值模拟表明，有非常简单的空间结构与间歇性的涡度区域。特别是，在对比的经典描述的湍流作为一个阵列的“煎饼”或“lasagne”样的eddies4，我们发现，高振幅涡结构是管状的，它们产生的局部速度场，螺旋围绕他们。
ALTHOUGH well developed turbulence exhibits complex, chaotic spatial and temporal behaviour, there is much experimental evidence to suggest that a remarkable degree of coherence is also present1. It is known2that correlations in small-scale turbulent motions show significant deviations from the gaussian statistics usually expected for large, randomly interacting systems. This phenomenon, known as intermittency, has long resisted analytical description because of the lack of a simple, universal characterization of turbulence structures3. Here we report numerical simulations which show that there are remarkably simple spatial structures associated with intermittent regions of vorticity. In particular, in contrast to the classical description of turbulence as an array of 'pancake'- or 'lasagne'-like eddies4, we find that high-amplitude vortex structures are tube-like and that they generate local velocity fields that spiral around them.