Wave Breaking Across the Inner Shelf and Nearshore Regions

在内陆架区域，风和海浪驱动的上层海洋与底部接触，并被底部改变，这代表了一个仍然知之甚少的海洋区域。该区域作为物质在冲浪带和陆架之间运输的重要通道，代表了表面波开始在沉积物的动员和分布中发挥作用的区域。该地区的破波在从大气到水柱的动量传递中起着重要作用，可能对平均洋流的形式和强度有很强的控制作用，而平均洋流的形式和强度会随着破波事件的性质随深度的变化而变化。该项目将开发各种建模方法来研究从深水到浅水的深度范围内的波浪破碎，基于该团队最近在实验室环境中高分辨率大涡模拟破裂事件的经验，以及正在进行的开发波分辨和波平均模型的工作。该项目还将通过实验室参观、面向公众的信息科学讲座、公开讲座的网络广播和特拉华大学开放日的特别活动，为博士生的培训和K-12外展活动做出贡献。该研究将侧重于从深水断裂的拓扑结构过渡到浅水断裂的拓扑结构，在深水断裂的拓扑结构中，会产生一个跨越断裂事件的底面的涡环，而浅水断裂的拓扑结构中，断裂事件在横向上被一些区域所包围，在这些区域中，会产生以表面和底部为终点的垂直涡核。这两种拓扑之间的转换将被表示为中间深度和浅水行为之间的主要分界线。特别是，过渡区代表了从深水向浅水的转变，其中破碎对水平涡量的产生有重要贡献，在浅水中，破碎主要在与破碎波峰几何形状对应的长度尺度上主要贡献垂直涡量。这项工作将分为三个主题：(1)在从深水到浅水的相对水深范围内，使用基于大涡模拟和流体体积模型的高分辨率计算，详细检查了有限波峰长度的破裂，该模型之前在波浪水槽实验中验证了中等深度的破裂；(2)发展了现有的非流体静力学，波浪解析，(3)建立了单个破碎波的冲力模型，并给出了破碎事件在空间和时间上的随机分布公式，该模型跨越深水到浅水的深度范围。最后一个模型将在非流体静力学、波浪平均模型中实现，用于描述从海岸线到内大陆架的整个水深范围内的波浪驱动过程。

The inner shelf region, in which the wind and wave-driven upper ocean comes in contact with, and is modified by, the bottom, represents a still poorly understood region of the ocean. The region is important as a pathway for the transport of materials between the surf zone and shelf, and represents the area where surface waves begin to play a role in the mobilization and distribution of sediments. Wave breaking in this region plays an important role in momentum transfer from atmosphere to water column and likely provides a strong control on the form and strength of mean currents which would shift as the nature of breaking events changes with depth. The project will develop a variety of modeling approaches to study wave breaking in the range of depths from deep to shallow water, building on this team's recent experience in high resolution Large Eddy Simulation of breaking events in laboratory settings, and on ongoing work in developing wave resolving and wave-averaged models for dispersive wave processes. The project will also contribute to the training of a Ph.D. student and K-12 outreach activities through laboratory visits and informational scientific talks to the public, web broadcasting of public lectures, and special events at open houses at the University of Delaware.The study will focus on a transition from the topology of deep water breaking, where a vortex ring spanning the underside of the breaking event is generated, and shallow water breaking, where the breaking event is laterally bounded by regions in which vertical vortex cores ending at the surface and bottom are generated. The transition between these two topologies will be denoted as a principal demarcation between intermediate depth and shallow water behavior. In particular, the transition region represents a shift from deeper water, with breaking making a significant contribution to horizontal vorticity generation, to shallow water, where breaking primarily contributes to predominantly vertical vorticity at length scales corresponding to breaking wave crest geometries. This effort will be organized in three main topics: (1) detailed examination of breaking of finite crest lengths in a range of relative water depths spanning from deep to shallow water, using high resolution calculations based on a combined Large Eddy Simulation and Volume of Fluid model previously verified for intermediate depth breaking in wave flume experiments, (2) development of extensions to an existing non hydrostatic, wave-resolving, shock-capturing solver for surface wave breaking to improve the representation of intermediate and deep water wave breaking, for application to larger spatial scales, and (3) development of an impulsive force model for individual breaking waves, together with a stochastic formulation for the distribution of breaking events in space and time, which spans the depth range from deep to shallow water. This last model will be implemented in a non hydrostatic, wave-averaged model for use in describing wave-driven processes in the full range of water depths from shoreline to inner shelf.