近日，英国牛津大学的M. L. McAllister及其研究团队对三维波破碎进行了研究。相关研究成果已于2024年9月18日在国际权威学术期刊《自然》上发表。

该研究团队展示了实验结果，评估了在不限制波浪传播方向的情况下，三维特性如何影响波浪破碎。研究发现，方向分布最广情况下的破碎起始陡度是其单向对应情况的两倍。研究人员确定了三种破碎状态。随着方向分布的增加，以二维破碎为基础的水平翻转“行波破碎”（I）被垂直喷射的“驻波破碎”（II）所取代。

在这两者之间，“行-驻波破碎”（III）的特征是沿快速移动的波峰形成垂直喷流。每种状态下的机制决定了，破碎如何限制陡度并影响随后的海气交换。与二维情况不同，三维波浪破碎的起始并不限制波浪可能达到的陡度，该研究产生的方向分布广泛的波浪陡度比破碎起始时高出80%，并且是等效二维波浪在破碎起始时陡度的四倍。这一观测结果对用于计算能量耗散，和在高方向分布海域设计海上结构物的，最先进方法的有效性提出了挑战。

据悉，尽管表面波破碎是一种普遍存在的自然现象，但其发生及随后的过程尚未完全明了。波破碎影响着波变得陡峭的程度，并驱动着海气交换。关于波破碎的大多数开创性及最前沿研究都是基于二维假设，尽管海洋波浪实际上是三维的。

附：英文原文

Title: Three-dimensional wave breaking

Author: McAllister, M. L., Draycott, S., Calvert, R., Davey, T., Dias, F., van den Bremer, T. S.

Issue&Volume: 2024-09-18

Abstract: Although a ubiquitous natural phenomenon, the onset and subsequent process of surface wave breaking are not fully understood. Breaking affects how steep waves become and drives air–sea exchanges. Most seminal and state-of-the-art research on breaking is underpinned by the assumption of two-dimensionality, although ocean waves are three dimensional. We present experimental results that assess how three-dimensionality affects breaking, without putting limits on the direction of travel of the waves. We show that the breaking-onset steepness of the most directionally spread case is double that of its unidirectional counterpart. We identify three breaking regimes. As directional spreading increases, horizontally overturning ‘travelling-wave breaking’ (I), which forms the basis of two-dimensional breaking, is replaced by vertically jetting ‘standing-wave breaking’ (II). In between, ‘travelling-standing-wave breaking’ (III) is characterized by the formation of vertical jets along a fast-moving crest. The mechanisms in each regime determine how breaking limits steepness and affects subsequent air–sea exchanges. Unlike in two dimensions, three-dimensional wave-breaking onset does not limit how steep waves may become, and we produce directionally spread waves 80% steeper than at breaking onset and four times steeper than equivalent two-dimensional waves at their breaking onset. Our observations challenge the validity of state-of-the-art methods used to calculate energy dissipation and to design offshore structures in highly directionally spread seas.

DOI: 10.1038/s41586-024-07886-z

Source: https://www.nature.com/articles/s41586-024-07886-z