Plunging breakers. Part 2. Droplet generation
Plunging breakers. Part 2. Droplet generation
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DOI：
10.1017/jfm.2023.378
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发表时间：
2022-10
影响因子：
3.7
通讯作者：
M. Erinin;Chang Liu;Sophie Wang;Xinan Liu;J. Duncan
中科院分区：
文献类型：
--
作者：
M. Erinin;Chang Liu;Sophie Wang;Xinan Liu;J. Duncan
本文对三种机械破碎波的动力学和液滴生成进行了实验研究。本文（第二部分）利用同轴电影全息术测量了第一部分中研究的三个倾入破碎波（Erinin等，流体力学杂志，vol.967，2023，A35），因为液滴向上移动穿过位于波峰正上方的水平测量平面。发现液滴产生有四种主要机制：关闭在俯冲射流的顶面和它所产生的飞溅之间的凹口，在冲击时捕获在俯冲射流下的大气泡的破裂，飞溅和泡沫破裂的湍流区的前面的波和破裂的小气泡，达到水面的波峰，破碎波跟随破碎机。每个断路器的整个液滴集的液滴直径分布与幂律函数拟合在单独的小直径和大直径区域。这些幂律函数交叉处的液滴直径从弱到强断路器分别从820单调增加到1480 $\mathrm {\mu }{\rm m}$。液滴的直径和速度特性和由四种机制产生的液滴的数量被发现显着不同，并讨论了创建这些差异的过程。
Abstract An experimental study of the dynamics and droplet production in three mechanically generated plunging breaking waves is presented in this two-part paper. In the present paper (Part 2), in-line cinematic holography is used to measure the positions, diameters ($d\geq 100\ \mathrm {\mu }{\rm m}$), times and velocities of droplets generated by the three plunging breaking waves studied in Part 1 (Erinin et al., J. Fluid Mech., vol. 967, 2023, A35) as the droplets move up across a horizontal measurement plane located just above the wave crests. It is found that there are four major mechanisms for droplet production: closure of the indentation between the top surface of the plunging jet and the splash that it creates, the bursting of large bubbles that were entrapped under the plunging jet at impact, splashing and bubble bursting in the turbulent zone on the front face of the wave and the bursting of small bubbles that reach the water surface at the crest of the non-breaking wave following the breaker. The droplet diameter distributions for the entire droplet set for each breaker are fitted with power-law functions in separate small- and large-diameter regions. The droplet diameter where these power-law functions cross increases monotonically from 820 to 1480 $\mathrm {\mu }{\rm m}$ from the weak to the strong breaker, respectively. The droplet diameter and velocity characteristics and the number of the droplets generated by the four mechanisms are found to vary significantly and the processes that create these differences are discussed.