Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographical references (leaves [111]-116).

Thesis (M.S.)--University of North Carolina Wilmington, 2009. / Title from PDF title page (February 23, 2010) Includes bibliographical references (109-111)

Thesis (M.S. in Meteorology and Physical Oceanography)--Naval Postgraduate School, Sept. 2004. / Thesis advisor(s): Timothy P. Stanton. Includes bibliographical references (p. 95-99). Also available online.

Thesis (Ph. D)--Université de Nantes, U.E.R. des sciences de la nature, 1978. / Includes bibliographical references (v. 1, leaves [114-121]).

Thesis (M.S.)--Joint Program in Oceanography/ Applied Ocean Science and Engineering, Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution, 2005. / Bibliography: p.63-65.

Thesis (M. S.)--Earth and Atmospheric Sciences, Georgia Institute of Technology, 2007. / Dr. Emanuele Di Lorenzo, Committee Member ; Dr. Ellery Ingall, Committee Member ; Dr. Martial Taillefert, Committee Chair.

Thesis (M.Oc.E.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 51-54). Also available on the World Wide Web.

Many environmental free surface flows involve water and sediment transport. The net changes to the surface level of an erodible bed by sediment entrainment and deposition processes have a feedback effect on the local ow hydrodynamics. Bed morphological change is of great socio-economic and environmental importance in that it affects navigation, flood risk management, water quality, species diversity, and overall river sustainability. This thesis describes a mathematical model of the depth-averaged shallow water-sediment equations based on mass and momentum conservation laws. A 2D numerical model is then presented of the fully coupled, variable-density governing equations, which are solved using a Godunov-type HLLC scheme. Dependent variables are specially selected in the numerical model to handle the presence of the variable-density mixture in the mathematical formulation. The model includes suspended sediment, bedload transport, and bed morphological change. The numerical model is verified against benchmark analytical and semi-analytical solutions for complicated, clear water flows, bedload transport and suspended sediment transport. The well-balanced property of the governing equations is verified for a variable-density dam break flow over a bed step. Simulations of an idealised dam-break flow over an erodible bed, in excellent agreement with previously published results, validate the ability of the model to capture complex water-sediment interactions under rapidly-varying flow conditions and a mobile bed, and validate the eigenstructure of the system of variable-density governing equations. The model is then further validated against laboratory based data for complex 2D partial dam breaks over fixed and mobile beds, respectively. The simulations of 2D dam break flows over mobile beds highlight the sensitivity of the results to the choice of closure relationships for sediment transport. To investigate this further, a parameter study is carried out using a variety of commonly used empirical formulae for suspended sediment transport. The numerical model is also used to inform a theoretical model that predicts the flow through and around a porous obstruction in a shallow channel. This problem is relevant to several practical applications, including flow through aquatic vegetation and the performance of arrays of tidal turbines in a finite-width tidal channel. The theoretical model is used to reinterpret the core flow velocities in laboratory-based data for an array of emergent cylinders in a shallow channel. Comparison with experimental data indicates the maximum obstacle resistance for which the theoretical model is valid. In a final application, the theoretical model examines the optimum arrangement of tidal turbines to generate power in a tidal channel, confirming that natural bed resistance increases the power extraction potential for a partial tidal fence.

Bed connected support structures such as monopiles are expected to be impractical for water depths greater than 30 m and so there is increasing interest in alternative structure concepts to enable cost-effective deployment of wind and tidal stream turbines. Floating, moored platforms supporting multiple rotors are being considered for this purpose. This thesis investigates the dynamic response of such floating structures, taking into account the coupling between loading due to both turbulent flow and waves and the dynamic response of the system. The performance and loading of a single rotor in steady and quasi-steady flows are quantified with a Blade Element Momentum Theory (BEMT) code. This model is validated for steady flow against published data for two 0.8 m diameter rotors (Bahaj, Batten, et al., 2007; Galloway et al., 2011) and a 0.27 m diameter rotor (Whelan and Stallard, 2011). Time-averaged coefficients of thrust and power measured by experiment in steady turbulent flow were in agreement with BEMT predictions over a range of angular speeds. The standard deviation of force on the rotor is comparable to that on a porous grid for comparable turbulence characteristics. Drag and added mass coefficients are determined for a porous disc forced to oscillate normal to the rotor plane in quiescent flow and in the streamwise axis in turbulent flow. Added mass is negligible for the Keulegan Carpenter number range considered ( less than 1). The drag coefficient in turbulent flow was found to decay exponentially with number, to 2±10% for values greater than 0.5. These coefficients were found to be in good agreement with those for a rotor in the same turbulent flow with disc drag coefficient within 12.5% for less than 0.65. An extreme-value analysis is applied to the measured time-varying thrust due to turbulent flow and turbulent flow with waves to obtain forces with 1%, 0.1% and 0.01% probability of exceedance during operating conditions. The 1% exceedance force in turbulent flow with turbulence intensity of 12% is around 40% greater than the mean thrust. The peak force in turbulent flow with opposing waves was predicted to within 6% by superposition of the extreme force due to turbulence only with a drag force based on the relative wave-induced velocity at hub-height estimated by linear wave theory and with drag coefficient of 2.0. Response of a floating structure in surge and pitch is studied due to both wave- forcing on the platform defined by the linear diffraction code WAMIT and due to loading of the operating turbine defined by a thrust coefficient and drag coefficient. Platform response can either increase or decrease the loading on the rotor and this was dependant on the hydrodynamic characteristics of the support platform. A reduction of the force on the rotor is attained when the phase difference between the wave force on the support and the surface elevation is close to ± and when the damping of the support is increased. For a typical support and for a wave condition with phase difference close to , the 1% rotor forces were reduced by 8% when compared to the force obtained with a rotor supported on a stiff tower.

The exchange of dissolved constituents between a shallow bay and the ocean is governed by regular tidal fluxes as well as by wind generated storm surges and currents. In this study the transport of a conservative tracer was simulated using the numerical model Delft3D in a system of shallow bays along the coast of the Delmarva Peninsula, Virginia. The evaluation of the tracer residence time was carried out using the Eulerian approach. The main mechanisms governing the decay of the tracer concentration inside the lagoons were assessed by considering the influence of different factors such as the time of release of the tracer with respect to the tidal cycle, tidal amplitude, and local winds. The exponential curve well approximates the decay of the tracer concentration in time. A set of simulations shows that the prevailing factor controlling the tracer transport and, therefore, the tracer concentration within the lagoons are wind-driven fluxes. Large tidal amplitudes also promote the flushing of the tracer out of the bay, while the time of tracer release with respect to the tidal phase has been found to play a relatively negligible role. Finally, a simplified approach is presented to compute the decay of tracer concentration in time. The method accounts for hourly variable wind characteristics as well as seasonal changes in meteorological conditions.