In response to Florida's growing energy needs and drive to develop renewable power, Florida Atlantic Universitys Center for Ocean Energy Technology (COET) plans to moor a 20 kW test turbine in the Florida Current. No permanent mooring systems for deepwater hydrokinetic turbines have been constructed and deployed, therefore little if anything is known about the performance of these moorings. To investigate this proposed mooring system, a numeric model is developed and then used to predict the static and dynamic behavior of the mooring system and attachments. The model has been created in OrcaFlex and includes two surface buoys and an operating turbine. Anchor chain at the end of the mooring line develops a catenary, providing compliance. Wind, wave, and current models are used to represent the environmental conditions the system is expected to experience and model the dynamic effects on the system. The model is then used to analyze various components of the system. The results identify that a mooring attachment point 1.25 m forward of the center of gravity on the mooring buoy is ideal, and that the OCDP and turbine tether lengths should be no shorter than 25 and 44 m, respectively. Analysis performed for the full system identify that the addition of the floats decreases the tension at the MTB attachment location by 26.5 to 29.5% for minimum current, and 0.10 to 0.31% for maximum current conditions. / by Allison Rose Cribbs. / Thesis (M.S.C.S.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.

This thesis describes a methodology for mechanical fault detection and diagnostics in an ocean turbine using vibration analysis and modeling. This methodology relies on the use of advanced methods for machine vibration analysis and health monitoring. Because of some issues encountered with traditional methods such as Fourier analysis for non stationary rotating machines, the use of more advanced methods such as Time-Frequency Analysis is required. The thesis also includes the development of two LabVIEW models. The first model combines the advanced methods for on-line condition monitoring. The second model performs the modal analysis to find the resonance frequencies of the subsystems of the turbine. The dynamic modeling of the turbine using Finite Element Analysis is used to estimate the baseline of vibration signals in sensors locations under normal operating conditions of the turbine. All this information is necessary to perform the vibration condition monitoring of the turbine. / by Mustapha Mjit. / Thesis (M.S.C.S.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.

This research focused on maximizing the power generated by an array of ocean current turbines. To achieve this objective, the produced shaft power of an ocean current turbine (OCT) has been quantified using CFD without adding a duct, as well as over a range of duct geometries. For an upstream duct, having a diameter 1.6 times the rotor diameter, the power increased by 8.35% for a duct that extends 1 diameter upstream. This research also focused on turbine array optimization, providing a mathematical basis for calculating the water velocity within an array of OCTs. After developing this wake model, it was validated using experimental data. As the downstream distance behind the turbine increases, the analytic results become closer to the experimental results, with a difference of 3% for TI = 3% and difference of 4% for TI = 15%, both at a downstream distance of 4 rotor diameters. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

A composite 3 meter ocean current turbine blade has been designed and analyzed using Blade Element Theory (BET) and commercial Finite Element Modeling (FEM) code, ANSYS. It has been observed that using the numerical BET tool created, power production up to 141 kW is possible from a 3 bladed rotor in an ocean current of 2.5 m/s with the proposed blade design. The blade is of sandwich construction with carbon fiber skin and high density foam core. It also contains two webs made of S2-glass for added shear rigidity. Four design cases were analyzed, involving differences in hydrodynamic shape, material properties, and internal structure. Results from the linear static structural analysis revealed that the best design provides adequate stiffness and strength to produce the proposed power without any structural failure. An Eigenvalue Buckling analysis confirmed that the blade would not fail from buckling prior to overstressed laminate failure if the loading was to exceed the Safety Factor. / by Nicholas S. Asseff. / Thesis (M.S.C.S.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.

by Shaun Hurley. / Thesis (M.S.C.S.)--Florida Atlantic University, 2011. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2011. Mode of access: World Wide Web. / The study presents a reliability-based fatigue life prediction model for the ocean current turbine rotor blades. The numerically simulated bending moment ranges based on the measured current velocities off the Southeast coast line of Florida over a one month period are used to reflect the short-term distribution of the bending moment ranges for an idealized marine current turbine rotor blade. The 2-parameter Weibull distribution is used to fit the short-term distribution and then used to obtain the long-term distribution over the design life. The long-term distribution is then used to determine the number of cycles for any given bending moment range. The published laboratory test data in the form of an ε-N curve is used in conjunction with the long-term distribution of the bending moment ranges in the prediction of the fatigue failure of the rotor blade using Miner's rule. The first-order reliability method is used in order to determine the reliability index for a given section modulus over a given design life. The results of reliability analysis are then used to calibrate the partial safety factors for load and resistance.

Submerged turbines which harvest energy from ocean currents are an important potential energy resource, but their harsh and remote environment demands an automated system for machine condition monitoring and prognostic health monitoring (MCM/PHM). For building MCM/PHM models, vibration sensor data is among the most useful (because it can show abnormal behavior which has yet to cause damage) and the most challenging (because due to its waveform nature, frequency bands must be extracted from the signal). To perform the necessary analysis of the vibration signals, which may arrive rapidly in the form of data streams, we develop three new wavelet-based transforms (the Streaming Wavelet Transform, Short-Time Wavelet Packet Decomposition, and Streaming Wavelet Packet Decomposition) and propose modifications to the existing Short-TIme Wavelet Transform. ... The proposed algorithms also create and select frequency-band features which focus on the areas of the signal most important to MCM/PHM, producing only the information necessary for building models (or removing all unnecessary information) so models can run on less powerful hardware. Finally, we demonstrate models which can work in multiple environmental conditions. ... Our results show that many of the transforms give similar results in terms of performance, but their different properties as to time complexity, ability to operate in a fully streaming fashion, and number of generated features may make some more appropriate than others in particular applications, such as when streaming data or hardware limitations are extremely important (e.g., ocean turbine MCM/PHM). / by Randall David Wald. / Thesis (Ph.D.)--Florida Atlantic University, 2012. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

An ocean turbine extarcts the kinetic energy from ocean currents to generate electricity. Machine Condition Monitoring (MCM) / Prognostic Health Monitoring (PHM) systems allow for self-checking and automated fault detection, and are integral in the construction of a highly reliable ocean turbine. MCM/PHM systems enable real time health assessment, prognostics and advisory generation by interpreting data from sensors installed on the machine being monitored. To effectively utilize sensor readings for determining the health of individual components, macro-components and the overall system, these measurements must somehow be combined or integrated to form a holistic picture. The process used to perform this combination is called data fusion. Data mining and machine learning techniques allow for the analysis of these sensor signals, any maintenance history and other available information (like expert knowledge) to automate decision making and other such processes within MCM/PHM systems. ... This dissertation proposes an MCM/PHM software architecture employing those techniques which were determined from the experiments to be ideal for this application. Our work also offers a data fusion framework applicable to ocean machinery MCM/PHM. Finally, it presents a software tool for monitoring ocean turbines and other submerged vessels, implemented according to industry standards. / by Janell A. Duhaney. / Thesis (Ph.D.)--Florida Atlantic University, 2012. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

This thesis proposes a sensor approach for quantifying the hydrodynamic performance of Ocean Current Turbines (OCT), and investigates the influence of sensor-specific noise and sampling rates on calculated turbine performance. Numerical models of the selected sensors are developed, and then utilized to add stochastic measurement error to numerically-generated, non-stochastic OCT data. Numerically-generated current velocity and turbine performance measurements are used to quantify the relative influence of sensor-specific error and sampling limitations on sensor measurements and calculated OCT performance results. The study shows that the addition of sensor error alters the variance and mean of OCT performance metric data by roughly 7.1% and 0.24%, respectively, for four evaluated operating conditions. It is shown that sensor error results in a mean, maximum and minimum performance metric to Signal to Noise Ration (SNR) of 48.6% and 6.2%, respectively. / by Matthew T. Young. / Thesis (M.S.C.S.)--Florida Atlantic University, 2012. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

The objective of this thesis is to analyze the flow past an ocean current turbine using a finite volume Navier-Stokes CFD solver. A full 3-D RANS approach in a moving reference frame is used to model the flow. By employing periodic boundary conditions, one-third of the flow-field is analyzed and the output is replicated to other sectors. Following validation of the computation with an experimental study, the flow fields and particle paths for the case of uniform and sheared incoming flows past a generic turbine with various blade pitch angles are evaluated and analyzed. Flow field and wake expansion are visualized. Eddy viscosity effects and its dependence on flow field conditions are investigated. / by Zaqie Reza. / Thesis (M.S.C.S.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.

The concept of marine current turbines was developed by Peter Fraenkel in the early 1970s. Ever since Fraenkel's efforts to modify and test the technology, several worldwide agencies have been exploiting the technology to retrofit the marine current turbine to their particular application. The marine current turbine has evolved from generating a few kilowatts to a few gigawatts. The present study focuses on a megawatt sized turbine to be located offshore the coast of Ft. Lauderdale, Florida. The turbine is to be placed in a similar location as a 20 kW test turbine developed by the Southeast National Marine Renewable Energy Center (SNMREC) at Florida Atlantic University, Dania Beach, FL. Data obtained from the SNMREC is used in the mathematical model. ANSYS FLUENT is chosen as the CFD software to perform wave-current interaction simulation for the present study. The turbine is modeled in SolidWorks, then meshed in ANSYS ICEM CFD, then run in FLUENT. The results obtained are compared to published work by scholarly articles from Fraenkel, Barltrop and many other well known marine energy researchers. The effects of wave height on the turbine operation are analyzed and the results are presented in the form of plots for tip speed ratio and current velocity. / by Amit J. SIngh. / Thesis (M.S.C.S.)--Florida Atlantic University, 2012. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2012. Mode of access: World Wide Web.