A new definition of the kinematic breaking onset criterion validated with solitary and quasi-regular waves in shallow water
A new definition of the kinematic breaking onset criterion validated with solitary and quasi-regular waves in shallow water
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DOI：
10.1016/j.coastaleng.2020.103755
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发表时间：
2021-03
影响因子：
4.4
通讯作者：
A. Varing;J. Filipot;S. Grilli;R. Duarte;V. Roeber;M. Yates
中科院分区：
文献类型：
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作者：
A. Varing;J. Filipot;S. Grilli;R. Duarte;V. Roeber;M. Yates
大量的工作致力于沿海地区波浪破碎的精确检测和模拟。它是处理广泛的工程活动和环境问题的关键过程。这促使了各种破裂起始标准的发展，例如基于波峰水平粒子速度与其相速度c之比的最大值(通常为1)的运动学标准，两者都在波的传播方向。在这里，我们用Grilli和Subramanya(1996)的完全非线性势流(FNPF)模型，数值研究了该判据在捕捉孤立波和准规则二维浅水波破波时的有效性。利用该模型，模拟了孤立波在平面斜坡上的传播到倾覆，以及孤立波和准规则波在水下沙洲上的传播，两者都是数值精确的FNPF波。在所有情况下，海浪都会以溢出或俯冲的方式破碎，这是由波峰附近形成的破碎喷流引发的。结果表明，最大流体速度||u||m在自由面上的位置与翻转射流的起始点位置非常吻合。在此基础上，提出了一种新的破碎起始判据：||u||m/c≃1。与现有的基于波峰速度的破碎起始判据相比，该判据具有更强的普适性。
A large body of work has been devoted to the accurate detection and simulation of wave breaking in coastal areas. It is a key process for a wide range of engineering activities and environmental issues. This has motivated the development of a variety of breaking onset criteria, such as kinematic criteria based on a maximum value (usually unity) of the ratio u c/c, of the horizontal particle velocity at the wave crest u c to its phase velocity c, both taken in the direction of wave propagation. Here, we investigate numerically the validity of this criterion in capturing breaking onset for solitary and quasi-regular two-dimensional shallow water waves using the Fully Nonlinear Potential Flow (FNPF) model by Grilli and Subramanya (1996). With this model, the propagation up to overturning of solitary waves over plane slopes, and solitary and quasi-regular waves over a submerged bar, both initially specified as numerically exact FNPF waves, is simulated. In all cases, waves break as spilling or plunging breakers, initiated by the formation of a breaker jet near the wave crest. Results show that the location of the maximum fluid velocity|| u|| m on the free surface closely coincides with the location where the overturning jet is initiated. Based on this, a new breaking onset criterion is proposed as|| u|| m/c≃ 1, which is shown to be more universal for accurately detecting wave breaking initiation than existing criteria based on the crest velocity.