Experiments on solitary internal Kelvin waves
Experiments on solitary internal Kelvin waves
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孤立内开尔文波实验
DOI：
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发表时间：
1983
影响因子：
3.7
通讯作者：
T. Maxworthy
中科院分区：
文献类型：
--
作者：
T. Maxworthy
初步计算表明，地球自转的影响可能对海洋、湖泊和大气中大多数内波的动力学很重要。在这里，我们提出了一类这样的波，即孤立的内部开尔文波，其中的科氏力产生的分层流体中的波动是由压力梯度，因此改变波的振幅沿着其波峰的结构和属性的测量。我们确认，波速是独立的速率，系统旋转，只取决于分层和最大波幅。然而，旋转被证明有很大的影响，在这两个速率的振幅随时间变化和横流的波的结构。根据公认的理论，横向于传播方向的振幅呈指数变化。这导致波速随着离壁的距离增加而减小，这又要求波前向后弯曲，以便波作为一个整体以其最大振幅给定的速度传播。这样的前曲率不包含在现有的理论中。波的振幅的快速衰减被认为是由于在均匀流体中产生的惯性波的上方和下方的内部wave.And一个合理的成功缩放这种效果已经发现，我们还讨论了调整的波地转平衡和评论我们的结果应用到自然系统。
Elementary calculations indicate that the effect of the Earth's rotation is likely to be important in the dynamics of most internal waves in oceans, lakes and the atmosphere. Here we present measurements of the structure and properties of one class of such waves, namely solitary internal Kelvin waves, in which the Coriolis force generated by wave motion in a stratified fluid is opposed by a pressure gradient and hence change in wave amplitude along its crest. We confirm that the wave speed is independent of the rate at which the system rotates and depends only on the stratification and maximum wave amplitude. However, rotation is shown to have a large effect on both the rate at which the amplitude varies with time and the cross-stream’ structure of the wave. In accordance with well-established theory, the amplitude transverse to the direction of propagation varies exponentially. This results in a decreasing wave speed with increasing distance from the wall, which in turn requires the wave front be curved backwards in order for the wave as a whole to propagate at a speed given by its maximum amplitude. Such a front curvature is not contained within the available theories. The rapid decay of wave amplitude is found to be due to the generation of inertial waves in the homogeneous fluid above and below the internal wave, and a reasonably successful scaling of this effect has been found. We also discuss the adjustment of the waves to geostropic balance and comment on applications of our results to natural systems.