Nonlinear inertia-gravity wave-mode interactions in three dimensional rotating stratified flows

Nonlinear inertia-gravity wave-mode interactions in three dimensional rotating stratified flows
复制标题

三维旋转分层流中的非线性惯性重力波模相互作用

DOI：
--
复制
发表时间：
2009
期刊：
影响因子：
--
通讯作者：
Leslie M. Smith
Leslie M. Smith
中科院分区：
--
文献类型：
--
作者：
Mark Remmel;J. Sukhatme;Leslie M. Smith

文献摘要

被引文献

相似文献

为了研究分层Boussinesq流中重力波的动力学，推导出一个模型，该模型包括所有三个重力波模式的相互作用（GGG模型），不包括涉及涡模式的相互作用。GGG模型是弱湍流理论的自然延伸，它解释了精确的三重重力波共振。通过随机、大尺度、高频强迫对模型进行了数值检验。一个直接的观察是所谓的垂直剪切水平流（VSHF）的强劲增长。此外，还有能量的前向转移和非零频率（有时称为“快”）引力波模式的平衡。这些结果表明，重力波模式的相互作用本身是能够系统的尺度间的能量传输在分层流体。通过对GGG模型和Boussinesq全系统的数值模拟比较，发现在所考虑的Fr范围内（0.05 ≤ Fr ≤ 1），两个系统的VSHF都是最难求解的。当充分解决时，VSHF生长在GGG模型中更活跃。此外，VSHF被观察到形成在GGG模式比完整的Boussinesq系统中的温和的分层方案。最后，完全三维的非零频率重力波模式在这两个系统中平衡，它们与垂直波数的比例遵循类似的幂律。所获得的幂律斜率取决于Fr，并且在Fr = 0.05时接近-2（从上面开始），这是可以用我们的计算资源正确解决的最强分层
To investigate the dynamics of gravity waves in stratified Boussinesq flows, a model is derived that consists of all three-gravity-wave-mode interactions (the GGG model), excluding interactions involving the vortical mode. The GGG model is a natural extension of weak turbulence theory that accounts for exact three-gravity-wave resonances. The model is examined numerically by means of random, large-scale, high-frequency forcing. An immediate observation is a robust growth of the so-called vertically sheared horizontal flow (VSHF). In addition, there is a forward transfer of energy and equilibration of the nonzero-frequency (sometimes called “fast”) gravity-wave modes. These results show that gravity-wave-mode interactions by themselves are capable of systematic interscale energy transfer in a stratified fluid. Comparing numerical simulations of the GGG model and the full Boussinesq system, for the range of Froude numbers (Fr) considered (0.05 ≤ Fr ≤ 1), in both systems the VSHF is hardest to resolve. When adequately resolved, VSHF growth is more vigorous in the GGG model. Furthermore, a VSHF is observed to form in milder stratification scenarios in the GGG model than the full Boussinesq system. Finally, fully three-dimensional nonzero-frequency gravity-wave modes equilibrate in both systems and their scaling with vertical wavenumber follows similar power-laws. The slopes of the power-laws obtained depend on Fr and approach −2 (from above) at Fr = 0.05, which is the strongest stratification that can be properly resolved with our computational resources