Scale dependence of the alignment between strain rate and rotation in turbulent shear flow
Scale dependence of the alignment between strain rate and rotation in turbulent shear flow
复制标题
湍流剪切流中应变率和旋转之间的对齐的尺度依赖性
DOI：
10.1103/physrevfluids.1.064405
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发表时间：
2016
影响因子：
2.7
通讯作者：
Fiscaletti D
中科院分区：
文献类型：
--
作者：
Fiscaletti D
应变率张量EI的本征向量的统计对齐趋势的尺度依赖性，与涡度矢量，检查在平面湍流混合层的自保持区域。从直接数值模拟的数据进行过滤，在不同的长度尺度和概率密度函数之间的两个单位向量的对齐余弦的大小|ei·ω|进行检查。据观察，对齐的趋势是不敏感的并发大规模的速度波动，但定量影响并发大规模的速度梯度波动的性质。证实了小尺度（局地）涡度矢量优先与大尺度涡度矢量平行排列（背景技术）广泛的应变率本征向量e1，与与中间应变率本征向量平行排列的整体趋势相反[Hamlington，Phys.Fluids20，111703（2008）PHFLE61070-663110.1063/1.3021055]。当只包括来自表现出强涡旋的流动区域的数据时，即所谓的高涡度拟能蠕虫，相对于全局图像，对准趋势被夸大了。这些研究结果支持的概念，涡度拟能的生产，负责从大尺度到小尺度的湍流动能的净级联，是由涡度拉伸驱动的，由于之间的优先平行排列和非本地E1和强烈的旋涡蠕虫是运动学上的重要这一过程。
The scale dependence of the statistical alignment tendencies of the eigenvectors of the strain-rate tensor ei, with the vorticity vector, is examined in the self-preserving region of a planar turbulent mixing layer. Data from a direct numerical simulation are filtered at various length scales and the probability density functions of the magnitude of the alignment cosines between the two unit vectors |ei·ω̂| are examined. It is observed that the alignment tendencies are insensitive to the concurrent large-scale velocity fluctuations, but are quantitatively affected by the nature of the concurrent large-scale velocity-gradient fluctuations. It is confirmed that the small-scale (local) vorticity vector is preferentially aligned in parallel with the large-scale (background) extensive strain-rate eigenvector e1, in contrast to the global tendency forto be aligned in parallel with the intermediate strain-rate eigenvector [Hamlington , Phys. Fluids 20, 111703 (2008)PHFLE61070-663110.1063/1.3021055]. When only data from regions of the flow that exhibit strong swirling are included, the so-called high-enstrophy worms, the alignment tendencies are exaggerated with respect to the global picture. These findings support the notion that the production of enstrophy, responsible for a net cascade of turbulent kinetic energy from large scales to small scales, is driven by vorticity stretching due to the preferential parallel alignment betweenand nonlocal e1 and that the strongly swirling worms are kinematically significant to this process.
湍流混合层中同时发生的大规模速度波动对速度梯度张量的调制
影响因子：
3.7
作者：
Buxton O
通讯作者：
Buxton O
空间发展混合层中湍流/非湍流界面的统计
影响因子：
1.9
作者：
A. Attili;Juan C Cristancho;F. Bisetti
通讯作者：
F. Bisetti
影响因子：
3.7
作者：
Buxton, O. R. H.;Ganapathisubramani, B.
通讯作者：
Ganapathisubramani, B.