IUTAM Symposium on Turbulence in the Atmosphere and Oceans - Proceedings of the IUTAM Symposium on Turbulence in the Atmosphere and Oceans, Cambridge, UK, December 8 - 12, 2008
IUTAM Symposium on Turbulence in the Atmosphere and Oceans - Proceedings of the IUTAM Symposium on Turbulence in the Atmosphere and Oceans, Cambridge, UK, December 8 - 12, 2008
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IUTAM 大气和海洋湍流研讨会 - IUTAM 大气和海洋湍流研讨会论文集，英国剑桥，2008 年 12 月 8 日至 12 日
DOI：
10.1007/978-94-007-0360-5_2
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
Aspden J
中科院分区：
文献类型：
--
作者：
Aspden J
利用几何光学方法研究了大气和海洋中惯性重力波的产生。这种方法认为，在规定的时间依赖性，平衡流的小尺度波包的动力学。波包被假定为在所谓的波捕获制度，其中波的固有频率是可以忽略不计的多普勒频移相比。的动态减少到一些常微分方程描述的波包位置的演变，其波矢量，和三个标量场描述的波包振幅和偏振。该方法清楚地确定了两类波的生成过程：不平衡的不稳定性，与惯性重力波之间的线性相互作用，和自发生成，与涡流和惯性重力模式之间的转换。简单的稳定流和随机应变模型的应用进行了讨论。
The generation of inertia-gravity waves in the atmosphere and oceans is examined using a geometric-optics approach. This approach considers the dynamics of a small-scale wavepacket in prescribed time-dependent, balanced flows. The wavepacket is assumed to be in the so-called wave-capture regime, where the wave intrinsic frequency is negligible compared to the Doppler shift. The dynamics is reduced to a number of ordinary differential equations describing the evolution of the wavepacket position, of its wavevector, and of three scalar fields describing the wavepacket amplitude and polarisation. The approach clearly identifies two classes of wave-generation processes: unbalanced instabilities, associated with linear interactions between inertia-gravity waves, and spontaneous generation, associated with a conversion between vortical and inertia-gravity modes. Applications to simple steady flows and to random-strain models are discussed.