Modelling and Assessing Surge Wave Impacts on Hydrodynamic Mixing and Transport

海啸、洪水和风暴潮等极端自然事件是极具破坏性的现象，对人类健康和生态系统产生不利影响。此外，海啸和风暴活动将经历与气候变化相关的变化（就其强度和频率而言）。在沿海大风暴期间，浪涌引起显著的景观变化，并促使污染物和碎屑从陆地向水中迁移。也就是说，2011年东日本大地震后的海啸将大量内陆碎片推入海洋，相当于日本海岸线数千年的正常垃圾。浪涌具有短暂性和史无前例的性质。浪涌波的主要特征之一是水的自由表面在空间和时间上的快速变形。波的传播及其破碎在波锋附近产生强烈的湍流。湍流特性、自由表面变形和大量夹带空气之间的相互作用决定了激波中的混合和传输动力学。数值和实验模型扩展了我们在可持续发展背景下准确预测这些水害潜在风险的能力。提出的研究方案提高了我们对激流混合和湍流的认识。我们的目标是开发和实施计算和实验技术，以收集与各种湍流机制相关的详细证据，如剪切层，波浪破碎和流向平流二次流。确定主要的湍流流态将有助于我们研究激流引起的输运及其对碎片和污染物再分配的影响。人们越来越关注气候变化对天气、降水模式以及海啸和浪涌强度的影响。为了设计有弹性的社区，解决此类事件中的社会和生态系统脆弱性问题，了解水文灾害的详细水动力行为及其与周围环境的相互作用至关重要。这项研究的结果将帮助我们预测和减轻日益普遍的水害对湍流混合和运输的自然模式的影响。

Extreme natural events such as tsunamis, floods, and storm surges are highly destructive phenomena that adversely impact human health and ecosystem. Moreover, tsunamic and storm activities will undergo changes (in terms of their intensity and frequency) associated with climate change. During large coastal storms, surge waves induce significant landscape changes and prompt the transport of contaminants and debris from land to water. Namely, the tsunami after the Great East Japan Earthquake in 2011 pushed a vast amount of in-land debris into the ocean, equivalent to thousands of years of normal litter from Japan's coastline. Surge waves have a transient and unprecedented nature. One of the key features of the surge waves is the rapid spatial and temporal deformations of the water's free-surface. Wave propagation and its breaking create intense turbulent flow in the vicinity of the wave's front. The interplay between turbulent properties, free-surface deformation, and large quantities of entrained air governs the dynamics of mixing and transport in surge waves. Numerical and experimental modeling expand our capability to accurately predict the potential risks of these hydro-hazards in the context of sustainable development. The proposed research program enhances our understanding of surge-induced mixing and turbulence. We aim to develop and implement computational and experimental techniques to gather detailed evidence associated with various turbulence mechanisms, such as shear layer, wave breaking, and streamwise advective secondary flows. Identifying the dominant turbulent flow regimes will help us investigate the surge-induced transport and its implications on redistribution of debris and contaminants. There are rising concerns over the impacts of climate change on weather, precipitation patterns, and on the intensity of tsunami and surge waves. In order to design resilient communities and address the social and ecosystem vulnerability during such events, it is critical to understand the detailed hydrodynamic behaviour of hydro-hazards and their interactions with their surrounding environment. The outcome of this research will help us anticipate and mitigate the impacts of increasingly prevalent hydro-hazards on natural patterns of turbulent mixing and transport.