Sediment transport and morphological change can play an important role during extreme coastal flood events. In this thesis, a set of 2-D shallow water-sediment equations is derived that incorporate suspended sediment, bedload transport and bed morphological evolution. A balanced stage-discharge hyperbolic formulation is adopted, which is suitable for complex shallow flows such as large-scale inundation over natural terrain. The 2-D shallow water-sediment equations are solved using a second-order Godunov-type approximate Riemann solver on dynamically adaptive quad tree grids. The numerical model is capable of simulating large-scale flood inundation over complex terrain. A number of test cases have been presented to validate the numerical model. The thesis also presents results from wave overtopping experiments of a scale model of the Anchorsholme seawall, carried out at HR Wallingford. The measurements of water surface elevation time histories from focused and irregular wave tests should be useful for validating numerical models of wave overtopping. The 2D shallow water model has also been applied to simulate the coastal flood inundation of Walcott, Norfolk. Considerable care has been taken to include building configurations. The results reproduce the pattern of flooding experienced at Walcott in November 2007, and demonstrate the importance of the street layout in channelling flood water. A Lagrangian particle tracking model is also presented for predicting the near bed saltation of sediment particles. In order to achieve higher order of accuracy, a fourthorder Runge-Kutta scheme is used for time-integrating the equations of motion of a spherical particle. Particle saltation over a flat bed and over a uniform bed comprised of hemispherical particles are simulated in unidirectional flow. The nonlinear dynamics of the particle saltation is investigated, and both regular and chaotic motions are observed. The Lagrangian particle saltation model has also been extended to simulate sediment particle transport in tidal flow.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:642623 |
| Date | January 2010 |
| Creators | Yan, Kuo |
| Publisher | University of Oxford |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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