Speed and Acceleration of Droplets Generated by Breaking Wind‐Forced Waves
Speed and Acceleration of Droplets Generated by Breaking Wind‐Forced Waves
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DOI：
10.1029/2022gl098426
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发表时间：
2022-06
影响因子：
5.2
通讯作者：
M. Erinin;B. Néel;D. Ruth;M. Mazzatenta;R. Jaquette;F. Veron;L. Deike
中科院分区：
文献类型：
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作者：
M. Erinin;B. Néel;D. Ruth;M. Mazzatenta;R. Jaquette;F. Veron;L. Deike
本文报道了由机械和风力驱动的破水波产生的液滴大小、速度和加速度的实验室测量结果。无风流速度高达12 m/s，在水深23 m处波浪斜率为0.15 ~ 0.35。随机械波频率的不同，自由风流与波相速度之比在5.9 ~ 11.1之间。所有形态下的液滴粒径分布均可用两个幂律表示，30 ~ 600 μm范围内的液滴N(d)∝d−1,600 μm以上的液滴N(d)∝d−4。液滴的水平和垂直速度呈相关性，水平速度较慢的液滴更有可能向上移动。速度和加速度分布是不对称的，速度概率密度函数（pdf）由正态-逆-高斯分布描述。发现水平加速度PDF的形状接近于均匀和各向同性湍流中小颗粒的预测形状，而垂直分布遵循不对称的法向形状，表明两种加速度分量受不同物理过程的控制。
Laboratory measurements of droplet size, velocity, and accelerations generated by mechanically and wind‐forced water breaking waves are reported. The wind free stream velocity is up to 12 m/s, leading to wave slopes from 0.15 to 0.35 at a fetch of 23 m. The ratio of wind free stream and wave phase speed ranges from 5.9 to 11.1, depending on the mechanical wave frequency. The droplet size distribution in all configurations can be represented by two power laws, N(d) ∝ d−1 for drops from 30 to 600 μm and N(d) ∝ d−4 above 600 μm. The horizontal and vertical droplet velocities appear correlated, with drops with slower horizontal speed more likely to move upward. The velocity and acceleration distributions are found to be asymmetric, with the velocity probability density functions (PDFs) being described by a normal‐inverse‐Gaussian distribution. The horizontal acceleration PDF are found to follow a shape close to the one predicted for small particles in homogeneous and isotropic turbulence, while the vertical distribution follows an asymmetric normal shape, showing that both acceleration components are controlled by different physical processes.