Turbulent Transport of Spray Droplets in the Vicinity of Moving Surface Waves
Turbulent Transport of Spray Droplets in the Vicinity of Moving Surface Waves
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DOI：
10.1175/jpo-d-19-0003.1
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发表时间：
2019-06
影响因子：
3.5
通讯作者：
D. Richter;Anne E. Dempsey;P. Sullivan
中科院分区：
文献类型：
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作者：
D. Richter;Anne E. Dempsey;P. Sullivan
估计海面喷雾和气溶胶生成函数的常用技术是所谓的通量剖面法，其中固定高度浓度测量用于通过假设浓度剖面的形式来推断表面的通量。最简单的是，该方法假设喷雾发射和沉积之间达到平衡，并且在这些条件下，浓度分布遵循幂律形状。这项工作的目的是评估波对幂律理论的影响，并研究其在一系列液滴尺寸上的适用性。大涡模拟与拉格朗日液滴跟踪相结合，用于解决喷雾液滴在下表面移动的单色波上的湍流传输。波龄和液滴直径是变化的，并且发现液滴很大程度上受到其惯性（即它们无法精确地沿着流体流线行进）和波引起的湍流的影响。在所有波龄和大液滴中都发现垂直浓度分布与幂律理论的偏差。波边界层内液滴的动力学改变了它们的净垂直通量，因此，基于通量剖面方法的表面发射估计可能会产生显着的误差。在实践中，由此得出的结论是，通量剖面方法可能不适合大液滴，惯性和波引起的湍流的综合效应是其表面源估计持续扩散的原因。
A common technique for estimating the sea surface generation functions of spray and aerosols is the so-called flux–profile method, where fixed-height concentration measurements are used to infer fluxes at the surface by assuming a form of the concentration profile. At its simplest, this method assumes a balance between spray emission and deposition, and under these conditions the concentration profile follows a power-law shape. It is the purpose of this work to evaluate the influence of waves on this power-law theory, as well as investigate its applicability over a range of droplet sizes. Large-eddy simulations combined with Lagrangian droplet tracking are used to resolve the turbulent transport of spray droplets over moving, monochromatic waves at the lower surface. The wave age and the droplet diameter are varied, and it is found that droplets are highly influenced both by their inertia (i.e., their inability to travel exactly with fluid streamlines) and the wave-induced turbulence. Deviations of the vertical concentration profiles from the power-law theory are found at all wave ages and for large droplets. The dynamics of droplets within the wave boundary layer alter their net vertical fluxes, and as a result, estimates of surface emission based on the flux–profile method can yield significant errors. In practice, the resulting implication is that the flux–profile method may unsuitable for large droplets, and the combined effect of inertia and wave-induced turbulence is responsible for the continued spread in their surface source estimates.