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造成不利影响。此外，海啸和风暴活动将经历与气候变化相关的变化(就强度和频率而言)。在大型沿海风暴期间，涌浪会引起显著的地貌变化，并促使污染物和碎片从陆地转移到水中。也就是说，2011年日本东部大地震后的海啸将大量内陆垃圾推入海洋，相当于日本海岸线数千年的正常垃圾。涌浪具有瞬时性和史无前例的性质。涌浪的主要特征之一是水面在空间和时间上的快速变形。波的传播及其破裂在波阵面附近产生强烈的湍流。湍流性质、自由面变形和大量夹带空气之间的相互作用支配着涌浪中的混合和输送动力学。数值模拟和实验模拟增强了我们在可持续发展背景下准确预测这些水灾的潜在风险的能力。所提出的研究方案加强了我们对喘振诱导的混合和湍流的理解。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。确定主要的湍流流型将有助于我们研究涌浪引起的输运及其对碎屑和污染物再分布的影响。人们越来越担心气候变化对天气、降水模式以及海啸和巨浪强度的影响。为了设计具有复原力的社区并解决此类事件期间的社会和生态系统脆弱性，至关重要的是要了解水灾的详细水动力行为及其与周围环境的相互作用。这项研究的结果将有助于我们预测和减轻日益普遍的水文灾害对湍流混合和输送的自然模式的影响。

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.