论文标题
各向异性湍流中的能量频率载体：旋转湍流的应用
Energy-flux vector in anisotropic turbulence: application to rotating turbulence
论文作者
论文摘要
能量通量在能量湍流的分析中起关键作用。在各向同性湍流中，通量由标量作为波数幅度的函数给出。另一方面，各向异性湍流中的通量应是具有方向和大小的几何矢量，不仅取决于波数的大小，而且还取决于其方向。各向异性湍流中的能量频率矢量不能以用于各向同性通量的方式唯一确定。在这项工作中，我们提出了两种非线性能量转移的净局部位置和效率，我们提出了一种方法来通过使用Moore-Penrose倒数来确定各向异性湍流中的能量频率载体。根据直接数值模拟获得的能量传递速率，证明了强旋转湍流中的能量频率载体。发现能量频率矢量的方向与以惯性波为主的波数范围内的弱湍流理论的预测一致。然而，在本模拟中未观察到弱湍流范围和各向同性kolmogorov湍流范围之间的临界平衡预测的临界波数的能量通量。讨论了临界平衡与当前数值结果之间的这种差异，发现耗散在缓冲范围内的能量通量中起着重要作用。
Energy flux plays a key role in the analyses of energy-cascading turbulence. In isotropic turbulence, the flux is given by a scalar as a function of the magnitude of the wavenumber. On the other hand, the flux in anisotropic turbulence should be a geometric vector that has a direction as well as the magnitude, and depends not only on the magnitude of the wavenumber but also on its direction. The energy-flux vector in the anisotropic turbulence cannot be uniquely determined in a way used for the isotropic flux. In this work, introducing two ansatzes, net locality and efficiency of the nonlinear energy transfer, we propose a way to determine the energy-flux vector in anisotropic turbulence by using the Moore--Penrose inverse. The energy-flux vector in strongly rotating turbulence is demonstrated based on the energy transfer rate obtained by direct numerical simulations. It is found that the direction of the energy-flux vector is consistent with the prediction of the weak turbulence theory in the wavenumber range dominated by the inertial waves. However, the energy flux along the critical wavenumbers predicted by the critical balance in the buffer range between in the weak turbulence range and the isotropic Kolmogorov turbulence range is not observed in the present simulations. This discrepancy between the critical balance and the present numerical results is discussed and the dissipation is found to play an important role in the energy flux in the buffer range.
