Contributions to the wave-mean momentum balance in the surf zone
Contributions to the wave-mean momentum balance in the surf zone
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DOI：
10.1016/j.coastaleng.2016.12.007
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发表时间：
2017-03
影响因子：
4.4
通讯作者：
J. V. D. Werf;J. Ribberink;W. Kranenburg;K. Neessen;M. Boers
中科院分区：
文献类型：
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作者：
J. V. D. Werf;J. Ribberink;W. Kranenburg;K. Neessen;M. Boers
冲浪带中的平均(波平均)跨岸气流具有很强的垂直变化。很好地理解和预测这一平均速度剖面是至关重要的，因为它决定了沉积物等组分的平流输送，从而决定了海岸地貌的演变。大多数海岸水动力和地貌动力学模拟系统不能解决波浪运动问题，而波-流耦合是一个具有挑战性的课题。本文基于固定坡床上的详细波浪水槽速度测量，研究了控制平均波浪区水动力的应力和力。结果表明，波谷水平以下的正应力垂直分布比较均匀。与此同时，数据表明，有很大一部分集中在波谷和波峰之间。此外，还得出了断路器附近水平辐射应力梯度和垂直剪切应力梯度可以是同一量级的结论。虽然在三维平均流模拟系统中通常被忽略，但波动雷诺应力对平均剪应力有重要的贡献。用经典的[16]表达式可以很好地预测波谷水平以下的法向应力，考虑了波峰和波谷之间的贡献。[39]的模型再现了底部边界层以上波雷诺应力的主要趋势。
Mean (wave-averaged) cross-shore flow in the surfzone has a strong vertical variation. Good understanding and prediction of this mean velocity profile is of crucial importance, as it determines the advective transport of constituents, such as sediment, and consequently the coastal morphological evolution. Most modeling systems for coastal hydrodynamics and morphodynamics do no resolve the wave motion, and wave-current coupling is a challenging topic. This paper investigates stresses and forces that control mean surfzone hydrodynamics based on detailed wave flume velocity measurements above a fixed sloping bed including two breaker bars. The data show that the vertical distribution of normal stress below the wave trough level is fairly uniform. At the same time, the data suggest that a significant part is concentrated between the wave trough and crest level. Furthermore, it is concluded that the horizontal radiation stress gradients and the vertical shear stress gradients can be of the same order of magnitude in the vicinity of the breaker bar. Although usually ignored in 3D mean flow modeling systems, the wave Reynolds stress makes an important contribution to the mean shear stress. The normal stress below the wave trough level could be reasonably well predicted using the classical [16] expression, accounting for the contribution between wave crest and trough. The model of [39] reproduces the main trends in the wave Reynolds stresses above the bottom boundary layer.