Efficiency of energy and enstrophy transfers in periodical flows
Efficiency of energy and enstrophy transfers in periodical flows
复制标题
周期性流动中的能量和熵转移效率
DOI：
10.1063/5.0142848
复制
发表时间：
2023
影响因子：
4.6
通讯作者：
A. Stocchino
中科院分区：
文献类型：
--
作者：
A. De Leo;A. Stocchino
我们应用粗粒化技术来理解准二维弱湍流周期流中能量和熵的尺度间输运效率。所研究的周期性流动类似于潮汐通道中单色潮汐的传播，通过入口连接到公海。周期性流动与进水口的相互作用在宽尺度上产生了涡状结构，最近已经显示出相应的能量和熵通量如何随潮汐相变化其符号。在本研究中，我们有兴趣通过分析能量的湍流应力和应变率之间的几何排列，以及熵的涡度应力和大尺度涡度梯度，将分析扩展到非线性传递率的效率。我们的结果表明，根据周期的相位，能量在有限的尺度范围内有效地转移到更大的尺度（逆级联），而在非常小和非常大的尺度上观察到的直接能量级联效率要低得多。熵在直接级联和反向级联之间的转换方面表现出类似的行为，然而，所有的转移似乎都相对低效。
We apply coarse-graining technique to understand the efficiency of the scale-to-scale transport of energy and enstrophy in quasi-two-dimensional weakly turbulent periodic flow. The investigated periodic flow resembles the propagation of a monochromatic tide in a tidal channel, connected to open sea through an inlet. The interaction of the periodic flow with the inlet mouth generates vortical structures in a wide spectrum of scales and recently has been shown how the corresponding energy and enstrophy fluxes change their signs depending on tidal phase. In the present study, we are interested to extend the analysis to the efficiency of the nonlinear transfer rates by analyzing the geometric alignment between the turbulent stresses and the strain rates for the energy, and the vorticity stress and large scale vorticity gradient for the enstrophy. Our results suggest that, depending on the phase of the period, energy is efficiently transferred to larger scales (inverse cascade) in a finite range of scales, whereas the observed direct energy cascade for very small and very large scales is much less efficient. Enstrophy shows similar behaviors in terms of transitions between direct and inverse cascading, however, all transfers seem to be relatively inefficient.