Advection and the Efficiency of Spectral Energy Transfer in Two-Dimensional Turbulence.
Advection and the Efficiency of Spectral Energy Transfer in Two-Dimensional Turbulence.
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DOI：
10.1103/physrevlett.117.104501
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发表时间：
2016-08
影响因子：
8.6
通讯作者：
L. Fang;N. Ouellette
中科院分区：
文献类型：
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作者：
L. Fang;N. Ouellette
我们报告的小尺度的湍流应力和大尺度的应变率，一起导致净通量的能量从小尺度到大尺度的二维湍流的几何对齐的测量。我们发现，这两个张量之间的瞬时对齐是弱的，因此，能量的光谱传输是低效的。然而，我们发现，应变率是更好地对准与应力在过去的时间，这表明差分平流的两个是负责效率低下的频谱传输。我们提供了这个猜想的证据，通过测量的对齐统计条件弱变化的应力历史。我们的研究结果提供了新的见解尺度到尺度的能量传递，几何对齐，和平流湍流之间的关系。
We report measurements of the geometric alignment of the small-scale turbulent stress and the large-scale rate of strain that together lead to the net flux of energy from small scales to large scales in two-dimensional turbulence. We find that the instantaneous alignment between these two tensors is weak and, thus, that the spectral transport of energy is inefficient. We show, however, that the strain rate is much better aligned with the stress at times in the past, suggesting that the differential advection of the two is responsible for the inefficient spectral transfer. We provide evidence for this conjecture by measuring the alignment statistics conditioned on weakly changing stress history. Our results give new insight into the relationship between scale-to-scale energy transfer, geometric alignment, and advection in turbulent flows.