View All Items

Title: Advanced Adaptive Torque Control of Hydrokinetic Turbines.
Creator: Ramirez, Juan, VanZwieten, James H.
Abstract/Description: Diversifying US energy production to include renewables has been a popular topic of discussion in recent years. In-stream hydrokinetic energy, electricity production from moving currents without the use of dams, has potential for significant power production with technically feasible US electricity production estimated at 14 GW from rivers, 50 GW from tides, and 19 GW from ocean currents; which is equivalent to approximately 17% of 2011 US power production. This work focuses on improving the...
Show moreDiversifying US energy production to include renewables has been a popular topic of discussion in recent years. In-stream hydrokinetic energy, electricity production from moving currents without the use of dams, has potential for significant power production with technically feasible US electricity production estimated at 14 GW from rivers, 50 GW from tides, and 19 GW from ocean currents; which is equivalent to approximately 17% of 2011 US power production. This work focuses on improving the power production from in-stream hydrokinetic turbines using adaptive torque control, and quantifies increased energy production by comparisons with standard fixed-gain torque control. This research uses numerical modeling to acquire power production estimates under simulated conditions. With these results we can quantify potential energy gains for three representative in-stream hydrokinetic rotor designs.
Show less
Date Issued: 2014
PURL: http://purl.flvc.org/fau/fd/FA0005035
Subject Headings: College students --Research --United States.
Format: Document (PDF)

Title: Experimental Hydrodynamic Performance Assessment Of the SNMREC’s 20 kW Ocean Current Turbine.
Creator: Young, Matthew T., VanZwieten, James H., Graduate College
Date Issued: 2011-04-08
PURL: http://purl.flvc.org/fcla/dt/3172440
Subject Headings: Water-power --Technological innovations --United States, Fluid dynamics, Ocean currents
Format: Document (PDF)

Title: Model-based global assessment of ocean thermal energy conversion (OTEC) power potential.
Creator: Rauchenstein, Lindy, Hanson, Howard P., VanZwieten, James H., Dhanak, Manhar R., Graduate College
Date Issued: 2011-04-08
PURL: http://purl.flvc.org/fcla/dt/3170913
Subject Headings: Ocean thermal power plants, Solar energy, Continental margins
Format: Document (PDF)

Title: Adaptive Control of In-Stream Ocean Current Turbines for Load Reduction.
Creator: Lee, Louis M., VanZwieten, James H., Office of Undergraduate Research and Inquiry
Abstract/Description: The ocean currents off Florida are a renewable and energy dense resource capable of providing Florida with about 25% of its electricity needs. This current is strongest at the sea surface and decreases in strength with depth such that the individual rotor blades on ocean current turbines (OCT) deployed to harness this resource will operate in stronger currents when positioned vertically upwards than when vertically downwards. This current shear will induce cyclic loadings on the rotor blades...
Show moreThe ocean currents off Florida are a renewable and energy dense resource capable of providing Florida with about 25% of its electricity needs. This current is strongest at the sea surface and decreases in strength with depth such that the individual rotor blades on ocean current turbines (OCT) deployed to harness this resource will operate in stronger currents when positioned vertically upwards than when vertically downwards. This current shear will induce cyclic loadings on the rotor blades unless active control is used to reduce these load variations. A direct adaptive individual blade pitch controller is implemented into a numerical model simulating an OCT operating in the Gulf Stream. The adaptive controller is analyzed with the OCT simulated in both stationary and moored configurations. The results concluded that the IBP controller reduced the amplitude of the loads in the stationary and moored simulations by 91.18% and 92.3%, respectively.
Show less
Date Issued: 2016
PURL: http://purl.flvc.org/fau/fd/FA00005582
Subject Headings: College students --Research --United States.
Format: Document (PDF)

Title: A Measurement Based Analysis of the Hydrokinetic Energy in the Gulf Stream.
Creator: Machado, Maria Carolina P. M., VanZwieten, James H.
Date Issued: 2015
PURL: http://purl.flvc.org/fau/fd/FAUIR000361
Format: Citation

Title: Computational Fluid Dynamics Prediction of a Modified Savonius Wind Turbine with Novel Blade Shapes.
Creator: Tian, Wenlong, Song, Baowei, VanZwieten, James H., Pyakurel, Parakram
Date Issued: 2015-07-30
PURL: http://purl.flvc.org/fau/fd/FAUIR000195
Format: Citation

Title: Numerical simulations of a horizontal axis water turbine designed for underwater mooring platforms.
Creator: Tian, Wenlong, Song, Baowei, VanZwieten, James H., Pyakurel, Parakram, Li, Yanjun
Date Issued: 2016-01
PURL: http://purl.flvc.org/fau/fd/FAUIR000223
Format: Citation

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 back-end tool that is fed continuously updated data on the OCT’s orientation and velocities as the simulation is running. The custom designed code was written specifically so that it could operate within the OrcaFlex environment. An approach for numerically modeling the entire OCT system is presented, which accounts for the additional degree of freedom (rotor rotational velocity) that is not accounted for in the OrcaFlex equations of motion. The properties of the numerically modeled OCT were then set to match those of a previously numerically modeled Southeast National Marine Renewable Energy Center (SNMREC) OCT system and comparisons were made. Evaluated conditions include: uniform axial and off axis currents, as well as axial and off axis wave fields. For comparison purposes these conditions were applied to a geodetically fixed rotor, showing nearly identical results for the steady conditions but varied, in most cases still acceptable accuracy, for the wave environment. Finally, this entire moored OCT system was evaluated in a dynamic environment to help quantify the expected behavioral response of SNMREC’s turbine under uniform current.
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: Automatic Station Keeping of Small Twin Screw Boats.
Creator: VanZwieten, James H., Driscoll, Frederick R., Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: This work details the development of tools and controllers for station keeping control of twin screw vessels. A fundamental analysis is conducted of the dynamics of twin screw displacement hull vessels and their actuator systems, where the response characteristics and maneuverability are quantified through a series of full scale trials conducted in different environmental conditions while recording the environmental conditions, actuator states, and geodetic and inertial measurements. The data...
Show moreThis work details the development of tools and controllers for station keeping control of twin screw vessels. A fundamental analysis is conducted of the dynamics of twin screw displacement hull vessels and their actuator systems, where the response characteristics and maneuverability are quantified through a series of full scale trials conducted in different environmental conditions while recording the environmental conditions, actuator states, and geodetic and inertial measurements. The data from these maneuvers were repeatable from run to run and thus provide valuable benchmarks for several maneuvers and the measured actuator response provides valuable set points of performance characteristics/limitations for control development. A comprehensive general simulation of small twin screw displacement hull boats is developed as a tool to estimate ship and actuator responses in support of developing and tuning of control systems. The model and computer simulation is capable of modeling a wide range of the surface vessels, including their actuators and environmental conditions. This model proved to be accurate, when compared to the sea trial data, and model estimates have rms velocity errors for the various steady maneuvers of 1.2-4.6% for surge, 12.6-17.9% for sway, and 7.6-20.2% for yaw. A path following station keeping controller is developed that uses Lyapunov stability analysis to determine the path the vessel should follow to effectively eliminate position error. This controller showed good performance for several different environmental conditions. Encouraged by these finding, three additional station keeping control methodologies are developed for twin screw surface ships. All four of these controllers are examined for their robustness to environmental conditions, as well as their sensitivity to sensor precision, sensor update rates, and actuator limitations. All controllers are evaluated in sea state 4 yielding rms position errors from 3.3 to 16.2 m, the rms surge and sway accelerations are under 0.62 m/s , and the engine shifting frequencies are between 0.011 and 0.145 Hz. These four controllers are then tested over a wide range of environmental conditions, sensor precisions and update rates, and actuator response rates. The results from these tests give quantitative data that will aid in selecting the appropriate controller for a specific application, and will assist in selecting appropriate sensors.
Show less
Date Issued: 2007
PURL: http://purl.flvc.org/fau/fd/FA00012579
Subject Headings: Boats and boating--Design, Actuators--Testing, Fracture mechanics, Lyapunov functions
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: 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)

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: Spectral evaluation of motion compensated adv systems for ocean turbulence measurements.
Creator: Egeland, Matthew Nicklas, von Ellenrieder, Karl, VanZwieten, James H., Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: A motion compensated ADV system was evaluated to determine its ability to make measurements necessary for characterizing the variability of the ambient current in the Gulf Stream. The impact of IMU error relative to predicted turbulence spectra was quantified, as well as and the ability of the motion compensation approach to remove sensor motion from the ADV measurements. The presented data processing techniques are shown to allow the evaluated ADV to be effectively utilized for quantifying...
Show moreA motion compensated ADV system was evaluated to determine its ability to make measurements necessary for characterizing the variability of the ambient current in the Gulf Stream. The impact of IMU error relative to predicted turbulence spectra was quantified, as well as and the ability of the motion compensation approach to remove sensor motion from the ADV measurements. The presented data processing techniques are shown to allow the evaluated ADV to be effectively utilized for quantifying ambient current fluctuations from 0.02 to 1 Hz (50 to 1 seconds) for dissipation rates as low as 3x10-7. This measurement range is limited on the low frequency end by IMU error, primarily by the calculated transformation matrix, and on the high end by Doppler noise. Inshore testing has revealed a 0.37 Hz oscillation inherent in the towfish designed and manufactured as part of this project, which can nearly be removed using the IMU.
Show less
Date Issued: 2014
PURL: http://purl.flvc.org/fau/fd/FA00004191, http://purl.flvc.org/fau/fd/FA00004191
Subject Headings: Fluid dynamic measurements, Fluid mechanics -- Mathematical models, Motion control systems, Ocean atmosphere interaction, Ocean circulation, Turbulence, Wave motion, Theory of
Format: Document (PDF)

FAU Theses and Dissertations (6)	+ -
Southeast National Marine Renewable Energy Center (3)	+ -
FAU Graduate Student Research (2)	+ -
FAU Undergraduate Student Research (2)	+ -

College students --Research --United States. (2)	+ -
Fluid dynamics (2)	+ -
Ocean wave power (2)	+ -
Actuators--Testing (1)	+ -
Atmospheric circulation. (1)	+ -

Boats and boating--Design (1)	+ -
Computational fluid dynamics. (1)	+ -
Continental margins (1)	+ -
Fluid dynamic measurements (1)	+ -
Fluid dynamic measurements. (1)	+ -
Fluid mechanics -- Mathematical models (1)	+ -
Fracture mechanics (1)	+ -
Hydrodynamics -- Research (1)	+ -
Lyapunov functions (1)	+ -
Marine turbines -- Mathematical models (1)	+ -
Marine turbines--Automatic control (1)	+ -
Marine turbines--Mathematical models (1)	+ -
Marine turbines--Mathematical models. (1)	+ -
Marine turbines. (1)	+ -
Motion control systems (1)	+ -
Ocean atmosphere interaction (1)	+ -
Ocean circulation (1)	+ -
Ocean current energy (1)	+ -
Ocean currents (1)	+ -
Ocean energy resources (1)	+ -
Ocean thermal power plants (1)	+ -
Solar energy (1)	+ -
Structural dynamics (1)	+ -
Structural dynamics. (1)	+ -
Turbines--Design and construction. (1)	+ -

Electronic Thesis or Dissertation (6)	+ -
article (3)	+ -
abstract (2)	+ -
poster (1)	+ -
symposium presentation (1)	+ -

VanZwieten, James H. (13)	+ -
College of Engineering and Computer Science (6)	+ -
Department of Ocean and Mechanical Engineering (6)	+ -
Florida Atlantic University (5)	+ -
Pyakurel, Parakram (3)	+ -

Search In

Sort Results By:

Narrow results by:

Collection

Topical Subject

Genre

Type of Resource

Language

Creator

Format

Owner