Identifying turbulent energy distributions in real, rather than fourier, space.
Identifying turbulent energy distributions in real, rather than fourier, space.
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DOI：
10.1103/physrevlett.95.214501
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发表时间：
2005-11
影响因子：
8.6
通讯作者：
P. Davidson;B. Pearson
中科院分区：
文献类型：
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作者：
P. Davidson;B. Pearson
有人提出，在谱空间中，使用E（k）或T（k），比在真实的空间中，使用二阶或三阶结构函数，更容易观察到高雷诺数湍流的平衡范围特性。例如，-5/3定律通常比等效的2/3定律更容易在实验数据中看到。我们认为，这不是一个隐含的功能，一个真实的空间描述湍流。相反，这是因为二阶结构函数混合了小尺度和大尺度信息。为了解决这个问题，我们采用了一个实空间函数，即签名函数，它起着能量密度的作用，有点类似于E（k）。在这封信中，我们确定的形式的签名功能在各种湍流。我们发现，耗散范围的现象，如所谓的瓶颈效应，是明显的签名功能，而不存在的结构功能。
It has been suggested that the equilibrium-range properties of high-Reynolds number turbulence are more readily observed in spectral space, using E(k) or T(k), than in real space, using second- or third-order structure functions. For example, the -5/3 law is usually easier to see in experimental data than the equivalent 2/3 law. We argue that this is not an implicit feature of a real-space description of turbulence. Rather, it is because the second-order structure function mixes small and large-scale information. To remedy this problem we adopt a real-space function, the signature function, which plays the role of an energy density, somewhat analogous to E(k). In this Letter we determine the form of the signature function in a variety of turbulent flows. We find that dissipation-range phenomena, such as the so-called bottleneck effect, are evident in the signature function, while absent in the structure function.