The increasing exploitation of marine renewable energy resources will create novel and unprecedented levels of anthropogenic activities in many coastal locations across the UK. In particular, locations with extensive and exploitable tidal stream energy resources will see large and dense arrays of installations, driven by the aggregated and limited distribution of this resource. Whilst the number of installations exploiting tidal stream energy resources is increasing, the environment impacts of installations remain unknown. This uncertainty is linked to our poor knowledge of the ecological function and importance of the high-energy environments, characterised with mean current speeds exceeding 2 ms-1, which are required for commercially viable installations. This thesis aims to increase our understanding of deep-diving seabirds' (Alcidae, Phalacrocoridae) use of high-energy environments, helping provide the information needed to estimate whether, which and when species could interact with installations. Chapters 3, 5 and 6 highlight the influence of predictable physical conditions (hydrodynamics, seabed features) on the foraging distributions of deep-diving seabirds across several spatial and temporal scales, indicating that the probable times and locations of foraging events within these habitats can be predicted. Chapter 4 directly tackles the estimation of spatial overlap between the foraging distributions of deep-diving seabirds and the locations of tidal stream turbines within a high-energy environment, evaluating and implementing methods to assess potential impacts at local and regional levels. Collectively, this thesis provides rare and novel studies into deep-diving seabirds' use of high-energy environments outside North America, and the only studies within these habitats that have collected quantitative and concurrent measurements of physical conditions and the foraging distributions of seabirds at fine spatial and temporal scales. In doing so, this thesis provides the empirical evidence needed to start identifying potential impacts from tidal stream energy extraction with more precision and confidence. By revealing the influence of predictable physical conditions on foraging events over several spatial and temporal scales, and also quantifying differences in habitat and microhabitat selection amongst deep-diving seabird species, this thesis also provides a unique contribution to our knowledge of the processes driving the foraging distributions of seabirds within coastal environments.

On August 5, 2010 the U.S. Department of Energy (DOE) has designated the Center for Ocean Energy Technology (COET) at Florida Atlantic University (FAU) as a national center for ocean energy research and development of prototypes for open-ocean power generation. Maintenance on ocean-based machinery can be very costly. To avoid unnecessary maintenance it is necessary to monitor the condition of each machine in order to predict problems. This kind of prognostic health monitoring (PHM) requires a condition-based maintenance (CBM) system that supports diagnostic and prognostic analysis of large amounts of data. Research in this field led to the creation of ISO13374 and the development of a standard open-architecture for machine condition monitoring. This thesis explores an implementation of such a system for ocean-based machinery using this framework and current open-standard technologies. / by Mark Bowren. / Thesis (M.S.C.S.)--Florida Atlantic University, 2012. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2012. Mode of access: World Wide Web.

This thesis describes a method to detect, localize and identify a faulty bearing in a rotating machine using narrow band envelope analysis across an array of accelerometers. This technique is developed as part of the machine monitoring system of an ocean turbine. A rudimentary mathematical model is introduced to provide an understanding of the physics governing the vibrations caused by a bearing with a raceway defect. This method is then used to detect a faulty bearing in two setups : on a lathe and in a dynamometer. / by Nicholas Waters. / Thesis (M.S.C.S.)--Florida Atlantic University, 2012. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

On August 5, 2010 the U.S. Department of Energy (DOE) has designated the Center for Ocean Energy Technology (COET) at Florida Atlantic University (FAU) as a national center for ocean energy research and development. Their focus is the research and development of open-ocean current systems and associated infrastructure needed to development and testing prototypes. The generation of power is achieved by using a specialized electric generator with a rotor called a turbine. As with all machines, the turbines will need maintenance and replacement as they near the end of their lifecycle. This prognostic health monitoring (PHM) requires data to be collected, stored, and analyzed in order to maximize the lifespan, reduce downtime and predict when failure is eminent. This thesis explores the use of a data gateway which will separate high level software with low level hardware including sensors and actuators. The gateway will v standardize and store the data collected from various sensors with different speeds, formats, and interfaces allowing an easy and uniform transition to a database system for analysis. / by Joseph. Gundel. / Thesis (M.S.C.S.)--Florida Atlantic University, 2012. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2012. Mode of access: World Wide Web.

Les hydroliennes font partie des dispositifs innovants d’énergie qui pourraient contribuer à ladiversification de la production d’électricité d’origine renouvelable. Les travaux réalisés dans le cadrede cette thèse avaient pour objet l’hydrolienne HARVEST, type d’hydrolienne constitué de turbines àflux transverse carénées ; il s’agissait, à partir d’un prototype complet, d’analyser l’interaction desdifférents phénomènes physiques mis en jeu et étudiés séparément jusqu’à lors, de valider les outilsnumériques développés au laboratoire LEGI et plus généralement de démontrer l’intérêt du concept.Ce prototype a été conçu, fabriqué, installé et testé dans un canal EDF à ciel ouvert situé près deGrenoble. Les résultats obtenus sont très encourageants en matière de performance énergétique, decomportement mécanique et de maîtrise de l’impact sur le cours d’eau. Ce mémoire se clôt par desconclusions d’ordre technologique des travaux présentés et sur une ouverture sur les possibilitésd’industrialisation du concept. / Instream water turbines belong to the innovative energy which could contribute to the diversificationof renewable power sources. Works done during this thesis aims at contributing to the overallobjective of developing the HARVEST turbine, a cross flow ducted turbines concept, in realizing andtesting an entire prototype to demonstrate the value of the concept, to understand physicalphenomena involved and to validate the numerical applications developed in the laboratory LEGI.This prototype has been put and tested in an EDF open channel near Grenoble. The results are veryencouraging in terms of energy performance, mechanical behavior and control of the impact on thewater channel. This memory is ending with technological conclusions on the presented work andopenings on the possibilities of industrialization of the concept.

Marine current turbines are submerged structures and subjected to loading conditions from both the currents and wave effects. The associated phenomena posed significant challenge to the analyses of the loading response of the rotor blades and practical limitations in terms of device location and operational envelopes. The effect of waves on marine current turbines can contribute to the change of flow field and pressure field around the rotor and hence changes the fluid forces on the rotor. However, the effect of the waves on the rotor depends on the magnitude and direction of flow velocity that is induced by the waves. An analysis is presented for predicting the torque, thrust, and bending moments resulting from the wave-current interactions at the root of rotor blades in a horizontal axis marine current turbine using the blade element-momentum (BEM) theory combined with linear wave theory. Parametric studies are carried out to better understand the influence of important parameters , which include wave height, wave frequency, and tip-speed ratio on the performance of the rotor. The periodic loading on the blade due to the steady spatial variation of current speeds over the rotor swept area is determined by a limited number of parameters, including Reynolds number, lift and drag coefficients, thrust and torque coefficients, and power coefficient. The results established that the BEM theory combined with linear wave theory can be used to analyze the wavecurrent interactions in full-scale marine current turbine. The power and thrust coefficients can be analyzed effectively using the numerical BEM theory in conjunction with corrections to the tip loss coefficient and 3D effects. / It has been found both thrust and torque increase as the current speed increases, and in longer waves the torque is relatively sensitive to the variation of wave height. Both in-plane and out-of-plane bending moments fluctuate significantly and can be predicted by linear wave theory with blade element-momentum theory. / by Junior Senat. / Thesis (M.S.C.S.)--Florida Atlantic University, 2011. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2011. Mode of access: World Wide Web.

This thesis is an approach of numerical optimization of thermal design of the ocean turbine developed by the Centre of Ocean Energy and Technology (COET). The technique used here is the integrated method of finite element analysis (FEA) of heat transfer, artificial neural network (ANN) and genetic algorithm (GA) for optimization purposes. / by Khaled Kaiser. / Thesis (M.S.C.S.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.

A computational tool has been developed by integrating National Renewable Energy Laboratory (NREL) codes, Sandia National Laboratories' NuMAD, and ANSYS to investigate a horizontal axis composite ocean current turbine. The study focused on the design, analysis, and life prediction of composite blade considering random ocean current, cyclic rotation, and hurricane-driven ocean current. A structural model for a horizontal axis FAU research OCT blade was developed. Following NREL codes were used: PreCom, BModes, ModeShape, AeroDyn and FAST. PreComp was used to compute section properties of the OCT blade. BModes and ModeShape calculated the mode shapes of the blade. Hydrodynamic loading on the OCT blade was calculated by modifying the inputs to AeroDyn and FAST. These codes were then used to obtain the dynamic response of the blade, including blade tip displacement, normal force (FN) and tangential force (FT), flap and edge bending moment distribution with respect to blade rotation. / by Fang Zhou. / Thesis (Ph.D.)--Florida Atlantic University, 2013. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

This thesis presents the analytically predicted position, motion, attitude, power output and forces on Florida Atlantic University's (FAU) first generation ocean current turbine for a wide range of operating conditions. These values are calculated using a 7- DOF dynamics simulation of the turbine and the cable that attaches it to the mooring system. The numerical simulation modifications and upgrades completed in this work include developing a wave model including the effects of waves into the simulation, upgrading the rotor model to specify the number of blades and upgrading the cable model to specify the number of cable elements. This enhanced simulation is used to quantify the turbine's performance in a wide range of currents, wave fields and when stopping and starting the rotor. For a uniform steady current this simulation predicts that when the rotor is fixed in 1.5 m/s current the drag on the turbine is 3.0 kN, the torque on the rotor is 384 N-m, the turbine roll and pitch are 2.4º and -1.2º . When the rotor is allowed to spin up to the rotational velocity where the turbine produces maximum power, the turbine drag increases to 7.3 kN, the torque increases to 1482 N-m, the shaft power is 5.8 kW, the turbine roll increases to 9º and the turbine pitch stays constant. Subsequently, a sensitivity analysis is done to evaluate changes in turbine performance caused by changes in turbine design and operation. This analysis show, among other things, that a non-axial flow on the turbine of up to 10º has a minimal effect on net power output and that the vertical stable position of the turbine varies linearly with the weight/buoyancy of the turbine with a maximum variation of 1.77 m for each increase or decrease of 1 kg at a current speed of 0.5 m/s. / by Nicolas Vanrietvelde. / Thesis (M.S.C.S.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.

The research presented in this thesis utilizes Blade Element Momentum (BEM) theory with a dynamic wake model to customize the OrcaFlex numeric simulation platform in order to allow modeling of moored Ocean Current Turbines (OCTs). This work merges the advanced cable modeling tools available within OrcaFlex with well documented BEM rotor modeling approach creating a combined tool that was not previously available for predicting the performance of moored ocean current turbines. This tool allows ocean current turbine developers to predict and optimize the performance of their devices and mooring systems before deploying these systems at sea. The BEM rotor model was written in C++ to create a back-end tool that is fed continuously updated data on the OCT’s orientation and velocities as the simulation is running. The custom designed code was written specifically so that it could operate within the OrcaFlex environment. An approach for numerically modeling the entire OCT system is presented, which accounts for the additional degree of freedom (rotor rotational velocity) that is not accounted for in the OrcaFlex equations of motion. The properties of the numerically modeled OCT were then set to match those of a previously numerically modeled Southeast National Marine Renewable Energy Center (SNMREC) OCT system and comparisons were made. Evaluated conditions include: uniform axial and off axis currents, as well as axial and off axis wave fields. For comparison purposes these conditions were applied to a geodetically fixed rotor, showing nearly identical results for the steady conditions but varied, in most cases still acceptable accuracy, for the wave environment. Finally, this entire moored OCT system was evaluated in a dynamic environment to help quantify the expected behavioral response of SNMREC’s turbine under uniform current. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2013.