Wave breaking in the ocean affects the height of extreme waves, energy dissipation, and interaction between the atmosphere and upper ocean. Numerical modelling is a critical step in understanding the physics of wave breaking and offers insight that is hard to gain from field data or experiments. High-fidelity numerical modelling of three-dimensional breaking waves is extremely challenging. Conventional grid-based numerical methods struggle to model the steep and double-valued free surfaces that occur during wave breaking. The Smoothed Particle Hydrodynamics (SPH) method does not fall prey to these issues. Herein, we examine the SPH method’s ability to model highly directionally spread overturning breaking waves by numerically reproducing the experiments presented in McAllister et al. (2019). We find that the SPH method reproduces the experimental observations well; when comparing experimental and numerical measurements we achieve coefficient of determination values of $0.92-0.95$, with some smaller-scale features less well reproduced owing to finite resolution. We also examine aspects of the simulated wave’s geometry and kinematics and find that existing breaking criteria are difficult to apply in highly directionally spread conditions.

海洋中的波浪破碎会影响极端波浪的高度、能量耗散以及大气与上层海洋之间的相互作用。数值建模是理解波浪破碎物理学的关键步骤，它提供了难以从现场数据或实验中获得的见解。三维破碎波的高保真数值建模极具挑战性。传统的基于网格的数值方法难以模拟波浪破碎期间出现的陡峭和双值自由表面。平滑粒子流体动力学 (SPH) 方法不会成为这些问题的牺牲品。在这里，我们通过数值再现 McAllister 等人提出的实验来检查 SPH 方法对高度定向传播的翻转破碎波进行建模的能力。(2019)。我们发现 SPH 方法很好地再现了实验观察结果；当比较实验和数值测量时，我们获得了决定系数值$0.92-0.95$，由于分辨率有限，一些小规模特征的再现效果较差。我们还检查了模拟波的几何形状和运动学的各个方面，发现现有的破碎标准难以应用于高度定向传播的条件。