Modelling and Assessing Surge Wave Impacts on Hydrodynamic Mixing and Transport

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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.