An understanding of natural coastal hazards is essential for improving resilience of coastal communities. Effective management of coastal hazards relies on prediction tools and mitigation structures that have been designed to handle the dynamic coastal system. This dissertation is a collection of manuscripts that cover a diverse range of fundamental...
To better understand the extreme local amplification of tsunami, the experimental investigation on counter-propagating solitary wave collisions over a horizontal bottom was conducted using the optical measurement techniques: Particle Image Velocimetry (PIV), and Laser Induced Fluoresce (LIF). Head-on collisions and oblique collisions of equal-amplitude as well as unequal-amplitude waves were...
Soil instability from tsunami hazards causes substantial damage to coastal infrastructure (e.g., the damage caused by the 2011 Great East Japan Tsunami, or the Heisei Tsunami). Tsunamis are unpredictable, so it is difficult to obtain field-scale measurements. Simulating tsunamis in a laboratory setting is therefore important to further understanding of...
Reflection of an obliquely incident solitary wave at a vertical wall is studied experimentally in the laboratory wave tank. Precision measurements of water-surface variations are achieved with the aid of laser-induced fluorescent (LIF) technique and detailed temporal and spatial features of the
Mach reflection are captured. During the development stage...
Numerical results are presented using a higher-order pseudo-spectral method in order to solve the Zakharov-Craig-Sulem formulation of the Euler model. We study the effects of variable bathymetry on weakly-dispersive, weakly-nonlinear, shallow water waves. Improved predictions on wave amplitude and shoaling behavior are developed by analytical means in the context of...
Wave runup is an important physical process that affects nearshore sediment transport, coastal erosion, and flooding. Large and unexpected runup events can also be dangerous to beach goers. Extreme runup statistics are essential parameters used in engineering design of marine structures and in coastal management. Although the study of runup...
The understanding and prediction how coastal wetland vegetation attenuates wave action has received renewed attention with global climate change impacts and increasing populations on coastlines. Conventional attenuation models utilize empirical drag coefficients, but these coefficients exhibit a wide range of values, and there is some uncertainty in the relative importance...
This dissertation has focused on the charateristics of bubbles generated by breaking waves and the feedback of wave-current interaction on the forcing mechanism of low frequency wave especially basin seiching wave. For the first study, Optical image capture observations of breaking waves in a laboratory surf zone are presented. The...
We describe spatio-temporal random processes using linear mixed models and discuss estimation, inference, and prediction under this formulation. We show how many commonly used covariances are special cases of this more general framework and pay special attention to the separable and product-sum covariances. The linear mixed model formulation facilitates straightforward...
A sewer geyser is a series of ejecting air-water mixture eruptions through vertical shafts of drainage systems. In field observed geyser incidents, manhole covers were blown into the air and they were followed by ejecting air-water mixture eruptions that lasted for several seconds at a time. Trapped air in sewer...