View All Items
(1 - 20 of 42)
Pages
- Title
- A FRAMEWORK FOR NON-INTRUSIVE OCEAN CURRENT TURBINE ROTOR BLADE IMBALANCE FAULT DETECTION.
- Creator
- Freeman, Brittny, Tang, Yufei, Florida Atlantic University, Department of Computer and Electrical Engineering and Computer Science, College of Engineering and Computer Science
- Abstract/Description
-
Ocean current turbines (OCT) convert the kinetic energy housed within the earth’s ocean currents into electricity. However, due to the harsh environmental conditions that these turbines operate in, their system performance naturally degrades over time. This degradation correlates to high operation and maintenance (O&M) costs, which necessitates the need for robust condition monitoring and fault detection (CMFD). Unfortunately, OCT operational data is not publicly available in large and/or...
Show moreOcean current turbines (OCT) convert the kinetic energy housed within the earth’s ocean currents into electricity. However, due to the harsh environmental conditions that these turbines operate in, their system performance naturally degrades over time. This degradation correlates to high operation and maintenance (O&M) costs, which necessitates the need for robust condition monitoring and fault detection (CMFD). Unfortunately, OCT operational data is not publicly available in large and/or diverse enough quantities to develop such frameworks. Therefore, from an industry-wide perspective, the technologies needed to harvest this energy source are still in their infancy.
Show less - Date Issued
- 2022
- PURL
- http://purl.flvc.org/fau/fd/FA00014094
- Subject Headings
- Marine turbines, Marine turbines--Blades
- Format
- Document (PDF)
- Title
- DESIGN, SIMULATION, AND TESTING OF A CVT BASED PTO AND CONTROLLER FOR A SMALL SCALE MHK-TURBINE IN LOW FLOW SPEED OPERATION.
- Creator
- Hall, Adam, Dhanak, Manhar, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
- Abstract/Description
-
The aim of this thesis project was to design, develop, and test, a continuously variable transmission (CVT)-based power take off (PTO) sub-system, and its controller, for a small scale marine hydrokinetic turbine (MHK) developed for low-speed tidal currents. In this thesis, a CVT based PTO and controller was developed for a predefined MHK and validated through simulations. A testing platform was subsequently developed including an emulation system to replicate the MHK for testing of the...
Show moreThe aim of this thesis project was to design, develop, and test, a continuously variable transmission (CVT)-based power take off (PTO) sub-system, and its controller, for a small scale marine hydrokinetic turbine (MHK) developed for low-speed tidal currents. In this thesis, a CVT based PTO and controller was developed for a predefined MHK and validated through simulations. A testing platform was subsequently developed including an emulation system to replicate the MHK for testing of the coupled MHK/PTO system. Laboratory testing of the emulation system, PTO component efficiencies, and full system with controls was then conducted. The results showed the mechanical PTO design to be a valid solution and the control methods to be marginally stable with adequate power conversion at low-speed current conditions. The results also identified future work in continued controller development, alternate PTO component testing, and continued testing in parallel with that being done on the MHK prototype.
Show less - Date Issued
- 2022
- PURL
- http://purl.flvc.org/fau/fd/FA00013977
- Subject Headings
- Marine turbines--Design and construction, Marine turbines--Transmission devices, Marine turbines--Testing
- Format
- Document (PDF)
- Title
- Estimates of water turbine noise levels.
- Creator
- Guerra, Julian., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
This work seeks to understand water turbine noise generation and to make preliminary estimations of the noise levels. Any structure attached to a turbine upstream its blades will generate unsteady fluctuating loads on the blade's surface, which are proportional to the radiated acoustic pressure. The noise levels of a simplified turbine based on existing designs surpass the ambient noise levels of the ocean at low frequencies ( 30 Hz).
Show moreThis work seeks to understand water turbine noise generation and to make preliminary estimations of the noise levels. Any structure attached to a turbine upstream its blades will generate unsteady fluctuating loads on the blade's surface, which are proportional to the radiated acoustic pressure. The noise levels of a simplified turbine based on existing designs surpass the ambient noise levels of the ocean at low frequencies (< 20 Hz) by approximately 50 dB ref 1 μPa and stay under the ambient noise levels at higher frequencies for a blade-passing frequency of 0.83 Hz and point of observation (100 m, 45 degrees, 45 degrees) from the hub. Streamlining the cross-section of the upstream structure as well as reducing its width decrease the noise levels by approximately 40 dB ref 1 μPa, at low frequencies and moderately increase them at higher frequencies. Increasing the structure-rotor distance decreases the noise levels with increasing frequencies (> 30 Hz).
Show less - Date Issued
- 2011
- PURL
- http://purl.flvc.org/FAU/3170958
- Subject Headings
- Turbines, Vibration, Testing, Underwater acoustics, Fluid dynamics
- Format
- Document (PDF)
- Title
- Numerical Simulation of Marine Hydrokinetic Turbines in Realistic Operating Conditions.
- Creator
- Dunlap, Broc, VanZwieten, James, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
- Abstract/Description
-
Marine Hydrokinetic (MHK) energy is an alternative to address the demand for cleaner energy sources. This study advanced numerical modeling tools and uses these to evaluate the performance of both a Tidal Turbine (TT) and an Ocean Current Turbine (OCT) operating in a variety of conditions. Inflow models are derived with current speeds ranging from 1.5 to 3 m/s and Turbulence Intensities (TI) of 5-15% and integrated into a TT simulation. An OCT simulation representing a commercial scale 20 m...
Show moreMarine Hydrokinetic (MHK) energy is an alternative to address the demand for cleaner energy sources. This study advanced numerical modeling tools and uses these to evaluate the performance of both a Tidal Turbine (TT) and an Ocean Current Turbine (OCT) operating in a variety of conditions. Inflow models are derived with current speeds ranging from 1.5 to 3 m/s and Turbulence Intensities (TI) of 5-15% and integrated into a TT simulation. An OCT simulation representing a commercial scale 20 m diameter turbine moored to the seafloor via underwater cable is enhanced with the capability to ingest Acoustic Doppler Current Profiler (ADCP) data and simulate fault conditions. ADCP measurements collected off the coast of Ft. Lauderdale during Hurricanes Irma and Maria were post-processed and used to characterize the OCT performance. In addition, a set of common faults were integrated into the OCT model to assess the system response in fault-induced scenarios.
Show less - Date Issued
- 2022
- PURL
- http://purl.flvc.org/fau/fd/FA00013962
- Subject Headings
- Turbines, Ocean wave power, Simulations, Mathematical models
- Format
- Document (PDF)
- Title
- SMALL UNMANNED MARINE HYDROKINETIC PLATFORMS FOR POWER GENERATION IN COASTAL AND TIDAL WATERS.
- Creator
- McKinney, Adriana, Dhanak, Manhar, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
- Abstract/Description
-
The feasibility and optimization of small unmanned mobile marine hydrokinetic (MHK) energy platforms for harvesting marine current energy in coastal and tidal waters are examined. A case study of a platform based on the use of a free-surface waterwheel (FSWW) mounted on an autonomous unmanned surface vehicle (USV) was conducted. Such platforms can serve as recharging stations for aerial drones (UAVs), enabling extension of the UAVs’ autonomous operating time. An unmanned MHK platform...
Show moreThe feasibility and optimization of small unmanned mobile marine hydrokinetic (MHK) energy platforms for harvesting marine current energy in coastal and tidal waters are examined. A case study of a platform based on the use of a free-surface waterwheel (FSWW) mounted on an autonomous unmanned surface vehicle (USV) was conducted. Such platforms can serve as recharging stations for aerial drones (UAVs), enabling extension of the UAVs’ autonomous operating time. An unmanned MHK platform potentially meets this need with sustainable power harvested from water currents. For the case study, six different waterwheel configurations were field-tested in the Intracoastal Waterway of South Florida in support of determining the configuration that produced the most power. Required technologies for unmanned operations of the MHK platform were developed and tested. The data from the field-testing were analyzed to develop an empirical relation between the wheel’s theoretical hydrokinetic power produced and the mechanical power harnessed by the MHK platform with various waterwheel configurations during field-testing. The field data was also used to determine the electrical power generated by the FSWW configurations during field-testing. The study has led to the development of standardized testing procedures. The empirical relation is used to examine predicted power production through scaling up different physical aspects of the waterwheel.
Show less - Date Issued
- 2024
- PURL
- http://purl.flvc.org/fau/fd/FA00014412
- Subject Headings
- Ocean engineering, Renewable energy, Marine turbines
- 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 hurricane-driven 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 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.
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
- Reliability-based 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 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...
Show moreThe 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.
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
- Optimization of an Ocean Current Turbine Design and Prediction of Wake Propagation in an Array.
- Creator
- Kawssarani, Ali, VanZwieten, James H., Seiffert, Betsy, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
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...
Show moreThis 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.
Show less - Date Issued
- 2018
- PURL
- http://purl.flvc.org/fau/fd/FA00013077
- Subject Headings
- Turbines--Design and construction., Marine turbines., Ocean current energy, Ocean wave power
- Format
- Document (PDF)
- Title
- Modeling and control of the "C-Plane" 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 "C-Plane" 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 C-Plane 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 C-Plane prototype is created to analyze this...
Show moreThe "C-Plane" 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 C-Plane 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 C-Plane 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 turbines--Automatic control, Ocean energy resources, Marine turbines--Mathematical models
- Format
- Document (PDF)
- Title
- DESIGN AND FAILURE ANALYSIS OF MULTI-COMPONENT MOORING LINES WITH NON-LINEAR POLYMER SPRINGS FOR FLOATING OFFSHORE WIND TURBINES.
- Creator
- McFadden, Jared, Mahfuz, Hassan, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
- Abstract/Description
-
This research studied the effects of mooring line pretension, spring safe working load, and spring response curve on peak loads and platform surge. The maximum tension load from the optimized assembly was applied to a modelled section of 8-strand multiplait rope to study stress concentrations. The analyses yielded a mooring line pretensioned at 1250 kN with a 4500 kN safe working load degressive spring was optimal. Fatigue damage from 12-hour duration of 50-year storm conditions was 8.04 × 10...
Show moreThis research studied the effects of mooring line pretension, spring safe working load, and spring response curve on peak loads and platform surge. The maximum tension load from the optimized assembly was applied to a modelled section of 8-strand multiplait rope to study stress concentrations. The analyses yielded a mooring line pretensioned at 1250 kN with a 4500 kN safe working load degressive spring was optimal. Fatigue damage from 12-hour duration of 50-year storm conditions was 8.04 × 10−6. Infinite life is predicted at annual average conditions. The peak tension from 50-year storm conditions of 3671 kN and annual average conditions of 1388 kN was applied to the section model, yielding a maximum stress of 3.70 × 108 Pa and 2.01 × 108 Pa, respectively, from friction and longitudinal compression of the rope’s cross section. The maximum stress from the static structural analysis was 33.5% of polyester’s ultimate strength, based on the maximum stress failure criterion.
Show less - Date Issued
- 2023
- PURL
- http://purl.flvc.org/fau/fd/FA00014245
- Subject Headings
- Wind turbines--Design and construction, Wind turbines--Testing, Deep-sea moorings
- Format
- Document (PDF)
- Title
- MODELING, IMPLEMENTATION AND CONTROL OF A CVT BASED PTO FOR A SMALL SCALE MHK-TURBINE IN LOW FLOW SPEED OPERATION.
- Creator
- Pimentel, Hugo, Dhanak, Manhar, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
- Abstract/Description
-
Modeling, implementation, field testing and control of a power takeoff (PTO) device equipped with a ball-type continuously variable transmission (B-CVT) for a small marine hydrokinetic (MHK) turbine deployed from a floating unmanned autonomous mobile catamaran platform is described. The turbine is a partially submerged multi-blade undershot waterwheel (USWW). A validated numerical torque model for the MHK turbine has been derived and a speed controller has been developed, implemented and...
Show moreModeling, implementation, field testing and control of a power takeoff (PTO) device equipped with a ball-type continuously variable transmission (B-CVT) for a small marine hydrokinetic (MHK) turbine deployed from a floating unmanned autonomous mobile catamaran platform is described. The turbine is a partially submerged multi-blade undershot waterwheel (USWW). A validated numerical torque model for the MHK turbine has been derived and a speed controller has been developed, implemented and tested in the field. The dependance of the power generated as a function of number and submergence level of turbine blades has been investigated and the number of blades that maximizes power production is determined. Bench and field testing in support of characterizing the power conversion capabilities of MHK turbine and PTO are described. Detailed results of the final torque and power coefficient models, the controls architecture, and the MHK turbine performance with varying numbers of blades are provided.
Show less - Date Issued
- 2024
- PURL
- http://purl.flvc.org/fau/fd/FA00014417
- Subject Headings
- Marine turbines, Renewable energy, Marine turbines--Transmission devices, Continuously variable transmission
- Format
- Document (PDF)
- Title
- Data gateway for prognostic health monitoring of ocean-based 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 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,...
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 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.
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
- Numerical models to simulate underwater turbine noise levels.
- Creator
- Lippert, Renee'., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
This work incorporates previous work done by Guerra and the application of fluid dynamics. The structure attached to the turbine will cause unsteady fluctuations in the flow, and ultimately affect the acoustic pressure. The work of Guerra is based on a lot of assumptions and simplifications to the geometry of the turbine and structure. This work takes the geometry of the actual turbine, and uses computational fluid dynamic software to numerically model the flow around the turbine structure....
Show moreThis work incorporates previous work done by Guerra and the application of fluid dynamics. The structure attached to the turbine will cause unsteady fluctuations in the flow, and ultimately affect the acoustic pressure. The work of Guerra is based on a lot of assumptions and simplifications to the geometry of the turbine and structure. This work takes the geometry of the actual turbine, and uses computational fluid dynamic software to numerically model the flow around the turbine structure. Varying the angle of the attack altered the results, and as the angle increased the noise levels along with the sound pulse, and unsteady loading increased. Increasing the number of blades and reducing the chord length both reduced the unsteady loading.
Show less - Date Issued
- 2012
- PURL
- http://purl.flvc.org/FAU/3355622
- Subject Headings
- Underwater acoustics, Mathematical models, Turbines, Vibration, Mathematical models, Fluid dynamics
- Format
- Document (PDF)
- Title
- Tidal Power Arrays and the Coriolis Force with Array Design Considerations.
- Creator
- Miglietta, Victoria, Dhanak, Manhar, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
- Abstract/Description
-
Tidal currents are a renewable energy resource and the work presented is in the field of harnessing tidal currents for electrical power generation. The main objective of the research is to provide information on rotational flow effects, caused by the spinning of the earth, around obstacles on the sea floor, in support of developing robust design of an underwater turbine array. This research looks at a gravity based linear array, a single turbine deep, with its largest dimension several...
Show moreTidal currents are a renewable energy resource and the work presented is in the field of harnessing tidal currents for electrical power generation. The main objective of the research is to provide information on rotational flow effects, caused by the spinning of the earth, around obstacles on the sea floor, in support of developing robust design of an underwater turbine array. This research looks at a gravity based linear array, a single turbine deep, with its largest dimension several kilometers long. The primary goal is to model a Taylor column above a linear array. The Taylor column has closed streamlines or stagnant flows inside of it and the flows around the column accelerate asymmetrically. The layout design of the array is intended to minimize the effect of the stagnant flows by predicting the location where closed streamlines could develop. The design is for the array and not for a turbine. Also, the locations where the energetic flows through the array have the longest periods are identified. Numerical modeling with ANSYS Fluent failed repeatedly to accurately model rotational effects around an obstacle with a minimal relative current so as to form a Taylor column. Instead, Johnson’s (1982) analytical solutions for quasigeostrophic flows over elongated topography are used to study how the blocking parameter influences streamlines with changes in velocity typical of a tidal change. The streamlines illustrate the location over an array where the flows are accelerated and also where closed streamlines form.
Show less - Date Issued
- 2019
- PURL
- http://purl.flvc.org/fau/fd/FA00013399
- Subject Headings
- Coriolis force, Tidal power, Renewable energy resources, Hydraulic turbines
- Format
- Document (PDF)
- Title
- Software framework for prognostic health monitoring of ocean-based 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 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...
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 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.
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, PATH PLANNING, AND CONTROL CO-DESIGN OF MARINE CURRENT TURBINES.
- Creator
- Hasankhani, Arezoo, Tang, Yufei, VanZwieten, James, Florida Atlantic University, Department of Computer and Electrical Engineering and Computer Science, College of Engineering and Computer Science
- Abstract/Description
-
Marine and hydrokinetic (MHK) energy systems, including marine current turbines and wave energy converters, could contribute significantly to reducing reliance on fossil fuels and improving energy security while accelerating progress in the blue economy. However, technologies to capture them are nascent in development due to several technical and economic challenges. For example, for capturing ocean flows, the fluid velocity is low but density is high, resulting in early boundary layer...
Show moreMarine and hydrokinetic (MHK) energy systems, including marine current turbines and wave energy converters, could contribute significantly to reducing reliance on fossil fuels and improving energy security while accelerating progress in the blue economy. However, technologies to capture them are nascent in development due to several technical and economic challenges. For example, for capturing ocean flows, the fluid velocity is low but density is high, resulting in early boundary layer separation and high torque. This dissertation addresses critical challenges in modeling, optimization, and control co-design of MHK energy systems, with specific case studies of a variable buoyancy-controlled marine current turbine (MCT). Specifically, this dissertation presents (a) comprehensive dynamic modeling of the MCT, where data recorded by an acoustic Doppler current profiler will be used as the real ocean environment; (b) vertical path planning of the MCT, where the problem is formulated as a novel spatial-temporal optimization problem to maximize the total harvested power of the system in an uncertain oceanic environment; (c) control co-design of the MCT, where the physical device geometry and turbine path control are optimized simultaneously. In a nutshell, the contributions are summarized as follows:
Show less - Date Issued
- 2022
- PURL
- http://purl.flvc.org/fau/fd/FA00013991
- Subject Headings
- Marine turbines, Modeling dynamic systems, Ocean wave power
- 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 S-N diagram with a frequency of 1 Hz and loading ratio 0.1 Number of specific load cycles from Rainflow Counting in conjunction with S-N diagram from ANSYS has been utilized to calculate fatigue damage up to 30 years by Palmgren-Miner'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 a Comprehensive Design Methodology and Fatigue Life Prediction of Composite Turbine Blades under Random Ocean Current Loading.
- Creator
- Suzuki, Takuya, Mahfuz, Hassan, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
A comprehensive study was performed to overcome the design issues related to Ocean Current Turbine (OCT) blades. Statistical ocean current models were developed in terms of the probability density function, the vertical profile of mean velocity, and the power spectral density. The models accounted for randomness in ocean currents, tidal effect, and ocean depth. The proposed models gave a good prediction of the velocity variations at the Florida Straits of the Gulf Stream. A novel procedure...
Show moreA comprehensive study was performed to overcome the design issues related to Ocean Current Turbine (OCT) blades. Statistical ocean current models were developed in terms of the probability density function, the vertical profile of mean velocity, and the power spectral density. The models accounted for randomness in ocean currents, tidal effect, and ocean depth. The proposed models gave a good prediction of the velocity variations at the Florida Straits of the Gulf Stream. A novel procedure was developed to couple Fluid-Structure Interaction (FSI) with blade element momentum theory. The FSI effect was included by considering changes in inflow velocity, lift and drag coefficients of blade elements. Geometric non-linearity was also considered to account for large deflection. The proposed FSI analysis predicted a power loss of 3.1 % due to large deflection of the OCT blade. The method contributed to saving extensive computational cost and time compared to a CFD-based FSI analysis. The random ocean current loadings were calculated by considering the ocean current turbulence, the wake flow behind the support structure, and the velocity shear. The random ocean current loadings had large probability of high stress ratio. Fatigue tests of GFRP coupons and composite sandwich panels under such random loading were performed. Fatigue life increased by a power function for GFRP coupons and by a linearlog function for composite sandwich panels as the mean velocity decreased. To accurately predict the fatigue life, a new fatigue model based on the stiffness degradation was proposed. Fatigue life of GFRP coupons was predicted using the proposed model, and a comparison was made with experimental results. As a summary, a set of new design procedures for OCT blades has been introduced and verified with various case studies of experimental turbines.
Show less - Date Issued
- 2017
- PURL
- http://purl.flvc.org/fau/fd/FA00005931
- Subject Headings
- Dissertations, Academic -- Florida Atlantic University, Turbines--Blades--Design and construction., Turbines--Blades--Materials., Composite construction--Fatigue., Ocean currents--Mathematical models.
- 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
- Turbulence--Mathematical models., Marine turbines--Mathematical models., Wind turbines--Aerodynamics--Mathematical models., Structural dynamics., Computational fluid dynamics., Fluid dynamic measurements., Atmospheric circulation.
- Format
- Document (PDF)
