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 Title
 Reliabilitybased fatigue design of marine current turbine rotor blades.
 Creator
 Hurley, Shaun., College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
 Abstract/Description

The study presents a reliabilitybased 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 shortterm distribution of the bending moment ranges for an idealized marine current turbine rotor blade. The 2parameter Weibull distribution is used to fit the shortterm distribution and then used to...
Show moreThe study presents a reliabilitybased 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 shortterm distribution of the bending moment ranges for an idealized marine current turbine rotor blade. The 2parameter Weibull distribution is used to fit the shortterm distribution and then used to obtain the longterm distribution over the design life. The longterm 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 εN curve is used in conjunction with the longterm distribution of the bending moment ranges in the prediction of the fatigue failure of the rotor blade using Miner's rule. The firstorder 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.
Show less  Date Issued
 2011
 PURL
 http://purl.flvc.org/FAU/3183123
 Subject Headings
 Turbines, Blades, Materials, Fatigue, Marine turbines, Mathematical models, Composite materials, Mathematical models, Structural dynamics
 Format
 Document (PDF)
 Title
 Data gateway for prognostic health monitoring of oceanbased power generation.
 Creator
 Gundel, Joseph., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
 Abstract/Description

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 openocean 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,...
Show moreOn 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 openocean 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.
Show less  Date Issued
 2012
 PURL
 http://purl.flvc.org/FAU/3342111
 Subject Headings
 Machinery, Monitoring, Marine turbines, Mathematical models, Fluid dynamics, Structural dynamics
 Format
 Document (PDF)
 Title
 Detection, localization, and identification of bearings with raceway defect for a dynamometer using high frequency modal analysis of vibration across an array of accelerometers.
 Creator
 Waters, Nicholas., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

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...
Show moreThis 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.
Show less  Date Issued
 2012
 PURL
 http://purl.flvc.org/FAU/3359156
 Subject Headings
 Marine turbines, Mathematical models, Vibration, Measurement, Fluid dynamics, Dynamic testing
 Format
 Document (PDF)
 Title
 Software framework for prognostic health monitoring of oceanbased power generation.
 Creator
 Bowren, Mark., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
 Abstract/Description

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 openocean power generation. Maintenance on oceanbased 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...
Show moreOn 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 openocean power generation. Maintenance on oceanbased 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 conditionbased 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 openarchitecture for machine condition monitoring. This thesis explores an implementation of such a system for oceanbased machinery using this framework and current openstandard technologies.
Show less  Date Issued
 2012
 PURL
 http://purl.flvc.org/FAU/3342035
 Subject Headings
 Machinery, Monitoring, Marine turbines, Mathematical models, Fluid dynamics, Structural dynamics
 Format
 Document (PDF)
 Title
 Modeling and control of the "CPlane" ocean current turbine.
 Creator
 VanZwieten, James H., Florida Atlantic University, Driscoll, Frederick R., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

The "CPlane" is a submerged ocean current turbine that uses sustained ocean currents to produce electricity. This turbine is moored to the sea floor and is capable of changing depth, as the current profile changes, to optimize energy production. A 1/30th scale physical prototype of the CPlane is being developed and the analysis and control of this prototype is the focus of this work. A mathematical model and dynamic simulation of the 1/30th scale CPlane prototype is created to analyze this...
Show moreThe "CPlane" is a submerged ocean current turbine that uses sustained ocean currents to produce electricity. This turbine is moored to the sea floor and is capable of changing depth, as the current profile changes, to optimize energy production. A 1/30th scale physical prototype of the CPlane is being developed and the analysis and control of this prototype is the focus of this work. A mathematical model and dynamic simulation of the 1/30th scale CPlane prototype is created to analyze this vehicle's performance, and aid in the creation of control systems. The control systems that are created for this prototype each use three modes of operation and are the Mixed PID/Bang Bang, Mixed LQR/PID/Bang Bang, and Mixed LQG/PID/Bang Bang control systems. Each of these controllers is tested using the dynamic simulation and Mixed PID/Bang Bang controller proves to be the most efficient and robust controller during these tests.
Show less  Date Issued
 2003
 PURL
 http://purl.flvc.org/fcla/dt/12980
 Subject Headings
 Marine turbinesAutomatic control, Ocean energy resources, Marine turbinesMathematical models
 Format
 Document (PDF)
 Title
 Hydrodynamic analysis of ocean current turbines using vortex lattice method.
 Creator
 Goly, Aneesh, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

The main objective of the thesis is to carry out a rigorous hydrodynamic analysis of ocean current turbines and determine power for a range of flow and geometric parameters. For the purpose, a computational tool based on the vortex lattice method (VLM) is developed. Velocity of the flow on the turbine blades, in relation to the freestream velocity, is determined through induction factors. The geometry of trailing vortices is taken to be helicoidal. The VLM code is validated by comparing its...
Show moreThe main objective of the thesis is to carry out a rigorous hydrodynamic analysis of ocean current turbines and determine power for a range of flow and geometric parameters. For the purpose, a computational tool based on the vortex lattice method (VLM) is developed. Velocity of the flow on the turbine blades, in relation to the freestream velocity, is determined through induction factors. The geometry of trailing vortices is taken to be helicoidal. The VLM code is validated by comparing its results with other theoretical and experimental data corresponding to flows about finiteaspect ratio foils, swept wings and a marine current turbine. The validated code is then used to study the performance of the prototype gulfstream turbine for a range of parameters. Power and thrust coefficients are calculated for a range of tip speed ratios and pitch angles. Of all the cases studied, the one corresponding to tip speed ratio of 8 and uniform pitch angle 20 produced the maximum power of 41.3 [kW] in a current of 1.73 [m/s]. The corresponding power coefficient is 0.45 which is slightly less than the Betz limit power coefficient of 0.5926. The VLM computational tool developed for the research is found to be quite efficient in that it takes only a fraction of a minute on a regular laptop PC to complete a run. The tool can therefore be efficiently used or integrated into software for design optimization.
Show less  Date Issued
 2010
 PURL
 http://purl.flvc.org/FAU/2683131
 Subject Headings
 Marine turbines, Mathematical models, Water currents, Forecasting, Mathematical models, Aerodynamics, Mathematics, Finite element method
 Format
 Document (PDF)
 Title
 Design and finite element analysis of an ocean current turbine blade.
 Creator
 Asseff, Nicholas S., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

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 S2glass for...
Show moreA 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 S2glass 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.
Show less  Date Issued
 2009
 PURL
 http://purl.flvc.org/FAU/221944
 Subject Headings
 Marine turbines, Mathematical models, Fluid dynamics, Structural dynamics, Composite materials, Mathematical models
 Format
 Document (PDF)
 Title
 Mathematical modeling of wavecurrent interactions in marine current turbines.
 Creator
 Singh, Amit J., College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
 Abstract/Description

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....
Show moreThe 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 wavecurrent 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.
Show less  Date Issued
 2012
 PURL
 http://purl.flvc.org/FAU/3352832
 Subject Headings
 Wave resistance (Thermodynamics), Structural design, Mathematical models, Laser Doppler velocimetry, Marine turbines, Mathematical models
 Format
 Document (PDF)
 Title
 Methodology for fault detection and diagnostics in an ocean turbine using vibration analysis and modeling.
 Creator
 Mjit, Mustapha., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

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 TimeFrequency Analysis is required. The thesis also includes the development of...
Show moreThis 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 TimeFrequency Analysis is required. The thesis also includes the development of two LabVIEW models. The first model combines the advanced methods for online 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.
Show less  Date Issued
 2009
 PURL
 http://purl.flvc.org/FAU/369198
 Subject Headings
 Marine turbines, Mathematical models, Fluid dynamics, Structural dynamics, Composite materials, Mathematical models, Elastic analysis (Engineering)
 Format
 Document (PDF)
 Title
 Fatigue modeling of composite ocean current turbine blade.
 Creator
 Akram, Mohammad Wasim, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

The success of harnessing energy from ocean current will require a reliable structural design of turbine blade that is used for energy extraction. In this study we are particularly focusing on the fatigue life of a 3m length ocean current turbine blade. The blade consists of sandwich construction having polymeric foam as core, and carbon/epoxy as face sheet. Repetitive loads (Fatigue) on the blade have been formulated from the randomness of the ocean current associated with turbulence and...
Show moreThe success of harnessing energy from ocean current will require a reliable structural design of turbine blade that is used for energy extraction. In this study we are particularly focusing on the fatigue life of a 3m length ocean current turbine blade. The blade consists of sandwich construction having polymeric foam as core, and carbon/epoxy as face sheet. Repetitive loads (Fatigue) on the blade have been formulated from the randomness of the ocean current associated with turbulence and also from velocity shear. These varying forces will cause a cyclic variation of bending and shear stresses subjecting to the blade to fatigue. Rainflow Counting algorithm has been used to count the number of cycles within a specific mean and amplitude that will act on the blade from random loading data. Finite Element code ANSYS has been used to develop an SN diagram with a frequency of 1 Hz and loading ratio 0.1 Number of specific load cycles from Rainflow Counting in conjunction with SN diagram from ANSYS has been utilized to calculate fatigue damage up to 30 years by PalmgrenMiner's linear hypothesis.
Show less  Date Issued
 2010
 PURL
 http://purl.flvc.org/FAU/2867332
 Subject Headings
 Turbines, Blades, Materials, Fatigue, Marine turbines, Mathematical models, Structural dynamics, Composite materials, Mathematical models, Sandwich construction, Fatigue
 Format
 Document (PDF)
 Title
 Development of an integrated computational tool for design and analysis of composite turbine blades under ocean current loading.
 Creator
 Zhou, Fang., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

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 hurricanedriven ocean current. A structural model for a horizontal axis FAU research OCT blade was developed. Following NREL codes were used...
Show moreA 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 hurricanedriven 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.
Show less  Date Issued
 2013
 PURL
 http://purl.flvc.org/fcla/dt/3362582
 Subject Headings
 Structural dynamics, Fluid dynamics, Marine turbines, Mathematical models, Turbines, Blades, Design and construction
 Format
 Document (PDF)
 Title
 Numerical Simulation of an Ocean Current Turbine Operating in a Wake Field.
 Creator
 Pyakurel, Parakram, VanZwieten, James H., Dhanak, Manhar R., Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

An Ocean Current Turbine (OCT) numerical simulation for creating, testing and tuning flight and power takeoff controllers, as well as for farm layout optimization is presented. This simulation utilizes a novel approach for analytically describing oceanic turbulence. This approach has been integrated into a previously developed turbine simulation that uses unsteady Blade Element Momentum theory. Using this, the dynamical response and power production of a single OCT operating in ambient...
Show moreAn Ocean Current Turbine (OCT) numerical simulation for creating, testing and tuning flight and power takeoff controllers, as well as for farm layout optimization is presented. This simulation utilizes a novel approach for analytically describing oceanic turbulence. This approach has been integrated into a previously developed turbine simulation that uses unsteady Blade Element Momentum theory. Using this, the dynamical response and power production of a single OCT operating in ambient turbulence is quantified. An approach for integrating wake effects into this single device numerical simulation is presented for predicting OCT performance within a farm. To accomplish this, far wake characteristics behind a turbine are numerically described using analytic expressions derived from wind turbine wake models. These expressions are tuned to match OCT wake characteristics calculated from CFD analyses and experimental data. Turbine wake is characterized in terms of increased turbulence intensities and decreased mean wake velocities. These parameters are calculated based on the performance of the upstream OCT and integrated into the environmental models used by downstream OCT. Simulation results are presented that quantify the effects of wakes on downstream turbine performance over a wide range of relative downstream and cross stream locations for both moored and bottom mounted turbine systems. This is done to enable the development and testing of flight and power takeoff controllers designed for maximizing energy production and reduce turbine loadings.
Show less  Date Issued
 2016
 PURL
 http://purl.flvc.org/fau/fd/FA00004737, http://purl.flvc.org/fau/fd/FA00004737
 Subject Headings
 TurbulenceMathematical models., Marine turbinesMathematical models., Wind turbinesAerodynamicsMathematical models., Structural dynamics., Computational fluid dynamics., Fluid dynamic measurements., Atmospheric circulation.
 Format
 Document (PDF)
 Title
 Design and analysis of an ocean current turbine performance assessment system.
 Creator
 Young, Matthew T., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

This thesis proposes a sensor approach for quantifying the hydrodynamic performance of Ocean Current Turbines (OCT), and investigates the influence of sensorspecific 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 numericallygenerated, nonstochastic OCT data. Numericallygenerated current velocity and turbine performance measurements are used to quantify the relative...
Show moreThis thesis proposes a sensor approach for quantifying the hydrodynamic performance of Ocean Current Turbines (OCT), and investigates the influence of sensorspecific 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 numericallygenerated, nonstochastic OCT data. Numericallygenerated current velocity and turbine performance measurements are used to quantify the relative influence of sensorspecific 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.
Show less  Date Issued
 2012
 PURL
 http://purl.flvc.org/FAU/3359164
 Subject Headings
 Marine turbines, Mathematical models, Fluid dynamics, Structural dynamics, Stochastic processes, Rotors, Design and construction, Testing
 Format
 Document (PDF)
 Title
 Dissipation and eddy mixing associated with flow past an underwater turbine.
 Creator
 Reza, Zaqie, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

The objective of this thesis is to analyze the flow past an ocean current turbine using a finite volume NavierStokes CFD solver. A full 3D RANS approach in a moving reference frame is used to model the flow. By employing periodic boundary conditions, onethird of the flowfield 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...
Show moreThe objective of this thesis is to analyze the flow past an ocean current turbine using a finite volume NavierStokes CFD solver. A full 3D RANS approach in a moving reference frame is used to model the flow. By employing periodic boundary conditions, onethird of the flowfield 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.
Show less  Date Issued
 2010
 PURL
 http://purl.flvc.org/FAU/2683537
 Subject Headings
 Vibration (Aerodynamics), Fine element method, Marine turbines, Mathematical models, Water currents, Forecasting, Computational fluid dynamics
 Format
 Document (PDF)
 Title
 Complete thermal design and modeling for the pressure vessel of an ocean turbine : a numerical simulation and optimization approach.
 Creator
 Kaiser, Khaled., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

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.
 Date Issued
 2009
 PURL
 http://purl.flvc.org/FAU/369194
 Subject Headings
 Thermal analysis, Computer programs, Heat exchangers, Design and construction, Marine turbines, Testing, Mathematical models, Fluid dynamics
 Format
 Document (PDF)
 Title
 Numerical performance prediction for FAU's first generation ocean current turbine.
 Creator
 Vanrietvelde, Nicolas., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

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...
Show moreThis 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 Nm, 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 Nm, 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 nonaxial 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.
Show less  Date Issued
 2009
 PURL
 http://purl.flvc.org/FAU/2182033
 Subject Headings
 Marine turbines, Mathematical models, Structural dynamics, Rotors, Design and construction, Testing, Fluid dynamics
 Format
 Document (PDF)
 Title
 Numerical simulation tool for moored marine hydrokinetic turbines.
 Creator
 Hacker, Basil L., Ananthakrishnan, Palaniswamy, VanZwieten, James H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

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...
Show moreThe 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 backend 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.
Show less  Date Issued
 2013
 PURL
 http://purl.flvc.org/fau/fd/FA0004024
 Subject Headings
 Fluid dynamics, Hydrodynamics  Research, Marine turbines  Mathematical models, Ocean wave power, Structural dynamics
 Format
 Document (PDF)
 Title
 Numerical simulation and prediction of loads in marine current turbine fullscale rotor blades.
 Creator
 Senat, Junior., College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
 Abstract/Description

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....
Show moreMarine 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 wavecurrent interactions at the root of rotor blades in a horizontal axis marine current turbine using the blade elementmomentum (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 tipspeed 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 fullscale 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 inplane and outofplane bending moments fluctuate significantly and can be predicted by linear wave theory with blade elementmomentum theory.
Show less  Date Issued
 2011
 PURL
 http://purl.flvc.org/FAU/3172695
 Subject Headings
 Marine turbines, Mathematical models, Structural dynamics, Fluid dynamics, Rotors, Design and construction
 Format
 Document (PDF)
 Title
 Vibration analysis for ocean turbine reliability models.
 Creator
 Wald, Randall David., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
 Abstract/Description

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...
Show moreSubmerged 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 waveletbased transforms (the Streaming Wavelet Transform, ShortTime Wavelet Packet Decomposition, and Streaming Wavelet Packet Decomposition) and propose modifications to the existing ShortTIme Wavelet Transform. ... The proposed algorithms also create and select frequencyband 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).
Show less  Date Issued
 2012
 PURL
 http://purl.flvc.org/FAU/3359158
 Subject Headings
 Marine turbines, Mathematical models, Fluid dynamics, Structural dynamics, Vibration, Measurement, Stochastic processes
 Format
 Document (PDF)
 Title
 A Power Quality Monitoring System for a 20 kW Ocean Turbine.
 Creator
 Cook, Kevin, Xiros, Nikolaos I., Florida Atlantic University
 Abstract/Description

This thesis explores an approach for the measurement of the quality of power generated by the Center of Ocean and Energy Technology's prototype ocean turbine. The work includes the development of a system that measures the current and voltage waveforms for all three phases of power created by the induction generator and quantifies power variations and events that occur within the system. These so called "power quality indices" are discussed in detail including the definition of each and how...
Show moreThis thesis explores an approach for the measurement of the quality of power generated by the Center of Ocean and Energy Technology's prototype ocean turbine. The work includes the development of a system that measures the current and voltage waveforms for all three phases of power created by the induction generator and quantifies power variations and events that occur within the system. These so called "power quality indices" are discussed in detail including the definition of each and how they are calculated using LabYiew. The results of various tests demonstrate that this system is accurate and may be implemented in the ocean turbine system to measure the quality of power produced by the turbine. The work then explores a dynamic model of the ocean turbine system that can be used to simulate the response of the turbine to varying conditions.
Show less  Date Issued
 2010
 PURL
 http://purl.flvc.org/fau/fd/FA00012514
 Subject Headings
 Marine turbinesMathematical models, Fluid dynamics, Power electronics, Finite element method
 Format
 Document (PDF)