Experimental study on large-scale streak structure in the core region of turbulent plane Couette flow
Experimental study on large-scale streak structure in the core region of turbulent plane Couette flow
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DOI：
10.1063/1.2844476
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发表时间：
2008-02
影响因子：
4.6
通讯作者：
O. Kitoh;M. Umeki
中科院分区：
文献类型：
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作者：
O. Kitoh;M. Umeki
物理实验证实Re=Uwh∕ν=3750处湍流库埃特流核心区存在大尺度条纹结构。在低速或高速条纹中存在大尺度的波状结构，其流向和展向波长分别为(40−65)h和(4−5)h。低（高）速条纹图案是一系列波状和非波状（斜线或不规则）图案。利用大尺度上具有高能量的流向脉动速度的小波分量来重建大尺度结构。重建的流场显示存在具有倾斜图案的大型结构。相对于流动方向的倾斜角度为±(3°−5°)。在一些地方，它们构成弱波浪图案，而在其他地方，它们构成简单的倾斜图案。弱波状结构沿水流方向间歇性地出现在空间中。粗略估计大型结构之间的流向分离时间为300h。
A physical experiment confirmed the existence of a large-scale streak structure in the core region of turbulent Couette flow at Re=Uwh∕ν=3750. In the low- or high-speed streak, large-scale wavy-like structures exist, the streamwise and spanwise wavelength of which are (40−65)h and (4−5)h. The low (high) -speed streak pattern is a sequence of wavy and nonwavy (tilted line or irregular) patterns. The large-scale structure is reconstructed using the wavelet components of the streamwise fluctuating velocity that have high energy on a large scale. The reconstructed flow field shows the existence of large-scale structures with a tilted pattern. The tilting angle is ±(3°−5°) against the flow direction. In some places, they constitute a weakly wavy pattern and in other places a simple tilted pattern. The weakly wavy structures appear intermittently in space along the streamwise direction. The rough estimation of the streamwise separation between large-scale structures is 300h.