A model of the free surface dynamics of shallow turbulent flows
A model of the free surface dynamics of shallow turbulent flows
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DOI：
10.1080/00221686.2016.1176607
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发表时间：
2016-01-01
影响因子：
2.3
通讯作者：
Shepherd, Simon J.
中科院分区：
文献类型：
--
作者：
Nichols, Andrew;Tait, Simon J.;Shepherd, Simon J.
了解地球物理流动的动态自由表面有可能使直接推断的流动特性的基础上测量的自由表面。一个重要的步骤是了解的固有响应的自由表面在深度有限的流动。在这里，提出了一个模型来证明，自由表面振荡的空间相关模式的结果，从个别的表面功能垂直振荡，因为它们在空间和时间上的平流。与实验室观测结果的比较表明，这些振荡的表面特征可以明确地解释由简谐运动，其中的振荡频率是由均方根水面波动，并在较小程度上的表面张力控制。这表明，所观察到的“复杂”波图案可以简单地描述为一个空间和时间分布的光子的合奏。近床突发事件的频率和估计的频率之间的相似性表明，湍流行为与相干流结构的创建。
Understanding the dynamic free surface of geophysical flows has the potential to enable direct inference of the flow properties based on measurements of the free surface. An important step is to understand the inherent response of free surfaces in depth-limited flows. Here a model is presented to demonstrate that free surface oscillatory spatial correlation patterns result from individual surface features oscillating vertically as they advect over space and time. Comparison with laboratory observations shows that these oscillating surface features can be unambiguously explained by simple harmonic motion, whereby the oscillation frequency is controlled by the root-mean-square water surface fluctuation, and to a lesser extent the surface tension. This demonstrates that the observed "complex" wave pattern can be simply described as an ensemble of spatially and temporally distributed oscillons. Similarities between the oscillon frequency and estimated frequency of near-bed bursting events suggest that oscillon behaviour is linked with the creation of coherent flow structures.