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Title: The acoustic far field of a turbulent boundary layer flow calculated from RANS simulations of the flow.
Creator: Blanc, Jean-Baptiste., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Boundary layers are regions where turbulence develops easily. In the case where the flow occurs on a surface showing a certain degree of roughness, turbulence eddies will interact with the roughness elements and will produce an acoustic field. This thesis aims at predicting this type of noise with the help of the Computational Fluid Dynamics (CFD) simulation of a wall jet using the Reynolds Average Navier-Stokes (RANS) equations. A frequency spectrum is reconstructed using a representation of...
Show moreBoundary layers are regions where turbulence develops easily. In the case where the flow occurs on a surface showing a certain degree of roughness, turbulence eddies will interact with the roughness elements and will produce an acoustic field. This thesis aims at predicting this type of noise with the help of the Computational Fluid Dynamics (CFD) simulation of a wall jet using the Reynolds Average Navier-Stokes (RANS) equations. A frequency spectrum is reconstructed using a representation of the turbulence with uncorrelated sheets of vorticity. Both aerodynamic and acoustic results are compared to experimental measurements of the flow. The CFD simulation of the flow returns consistent results but would benefit from a refinement of the grid. The surface pressure spectrum presents a slope in the high frequencies close to the experimental spectrum. The far field noise spectrum has a 5dB difference to the experiments.
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Date Issued: 2009
PURL: http://purl.flvc.org/FAU/368611
Subject Headings: Computational fluid dynamics, Turbulence, Mathematical models, Fluid mechanics, Mathematical models, Acoustical engineering
Format: Document (PDF)

Title: Aerodynamic analysis of a propeller in a turbulent boundary layer flow.
Creator: Lachowski, Felipe Ferreira., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Simulating the exact chaotic turbulent flow field about any geometry is a dilemma between accuracy and computational resources, which has been continuously studied for just over a hundred years. This thesis is a complete walk-through of the entire process utilized to approximate the flow ingested by a Sevik-type rotor based on solutions to the Reynolds Averaged Navier-Stokes equations (RANS). The Multiple Reference Frame fluid model is utilized by the code of ANSYS-FLUENT and results are...
Show moreSimulating the exact chaotic turbulent flow field about any geometry is a dilemma between accuracy and computational resources, which has been continuously studied for just over a hundred years. This thesis is a complete walk-through of the entire process utilized to approximate the flow ingested by a Sevik-type rotor based on solutions to the Reynolds Averaged Navier-Stokes equations (RANS). The Multiple Reference Frame fluid model is utilized by the code of ANSYS-FLUENT and results are validated by experimental wake data. Three open rotor configurations are studied including a uniform inflow and the rotor near a plate with and without a thick boundary layer. Furthermore, observations are made to determine the variation in velocity profiles of the ingested turbulent flow due to varying flow conditions.
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Date Issued: 2013
PURL: http://purl.flvc.org/fcla/dt/3360798
Subject Headings: Acoustical engineering, Boundary layer control, Multiphase flow, Mathematical models, Fluid mechanics, Mathematical models, Turbulence, Mathematical models, Computatioinal fluid dynamics
Format: Document (PDF)

Title: Analysis of ship hull and plate vibrations caused by wave forces.
Creator: Lakitosh, Fnu, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: In the present dissertation, the hydrodynamic and hydro-elastic characteristics of ship hull and plate vibrations are analyzed using theoretical and numerical methods. The wave forces are determined using a suite of methods which include the Froude-Krylov method for incident wave forces, Wagner's method and ABS rules for the slamming wave force, and numerical methods for nonlinear wave radiation forces. Finite difference methods are developed to determine the wave forced vibrations of ship...
Show moreIn the present dissertation, the hydrodynamic and hydro-elastic characteristics of ship hull and plate vibrations are analyzed using theoretical and numerical methods. The wave forces are determined using a suite of methods which include the Froude-Krylov method for incident wave forces, Wagner's method and ABS rules for the slamming wave force, and numerical methods for nonlinear wave radiation forces. Finite difference methods are developed to determine the wave forced vibrations of ship hull plates which are modeled using a range of plate theories including nonlinear plate theory with and without material damping and orthotropic plate theory for stiffened hull plates. For small amplitude deformation of thin plates, a semi-theoretical superposition method is used to determine the free and forced vibrations. The transient ship hull vibration due to whipping is also analyzed using the finite difference method. Results, in the form of deformations and stress distributions, are obtained for a range of scantling and wave parameters to identify key parameters to consider in ship structural design.
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Date Issued: 2012
PURL: http://purl.flvc.org/FAU/3342196
Subject Headings: Vibration (Marine engineering), Hulls (Naval architecture), Ships, Hydraulic impact, Ocean waves, Mathematical models, Fluid dynamics, Mathematical models
Format: Document (PDF)

Title: Characterizing magnetic noise of AUV for use in towed magnetometer study of internal waves.
Creator: Tilley, Dylan., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: As part of a project to study internal waves, FAU plans to utilize an AUV to tow a magnetometer to study electromagnetic signatures from internal waves. This research is focused on the electromagnetic noise issues related to using an AUV to tow the magnetic sensor package. There are active sources of electromagnetic noise caused by an AUV that are present in addition to those induced by the Earth's magnetic field and permanent magnets. To characterize the magnetic noise associated with the...
Show moreAs part of a project to study internal waves, FAU plans to utilize an AUV to tow a magnetometer to study electromagnetic signatures from internal waves. This research is focused on the electromagnetic noise issues related to using an AUV to tow the magnetic sensor package. There are active sources of electromagnetic noise caused by an AUV that are present in addition to those induced by the Earth's magnetic field and permanent magnets. To characterize the magnetic noise associated with the AUV magnetometer tow system, the various active source elements were identified, the orientation sensitivity of the sensors being used was determined, and the magnetic anomaly of a similar AUV which may be eventually be used in a magnetic sensing arrangement was measured. The results are used to show the proposed sensing arrangement will likely not achieve the necessary sensitivity to measure subtle internal wave signals.
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Date Issued: 2012
PURL: http://purl.flvc.org/FAU/3352881
Subject Headings: Automatic control, Mathematical models, Electromagnetic measurements, Fluctuations (Physics), Oceanographic submersibles, Underwater acoustics
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: 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 sensor-specific noise and sampling rates on calculated turbine performance. Numerical models of the selected sensors are developed, and then utilized to add stochastic measurement error to numerically-generated, non-stochastic OCT data. Numerically-generated current velocity and turbine performance measurements are used to quantify the relative...
Show moreThis thesis proposes a sensor approach for quantifying the hydrodynamic performance of Ocean Current Turbines (OCT), and investigates the influence of sensor-specific noise and sampling rates on calculated turbine performance. Numerical models of the selected sensors are developed, and then utilized to add stochastic measurement error to numerically-generated, non-stochastic OCT data. Numerically-generated current velocity and turbine performance measurements are used to quantify the relative influence of sensor-specific error and sampling limitations on sensor measurements and calculated OCT performance results. The study shows that the addition of sensor error alters the variance and mean of OCT performance metric data by roughly 7.1% and 0.24%, respectively, for four evaluated operating conditions. It is shown that sensor error results in a mean, maximum and minimum performance metric to Signal to Noise Ration (SNR) of 48.6% and 6.2%, respectively.
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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: 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 S2-glass 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 S2-glass for added shear rigidity. Four design cases were analyzed, involving differences in hydrodynamic shape, material properties, and internal structure. Results from the linear static structural analysis revealed that the best design provides adequate stiffness and strength to produce the proposed power without any structural failure. An Eigenvalue Buckling analysis confirmed that the blade would not fail from buckling prior to overstressed laminate failure if the loading was to exceed the Safety Factor.
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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: 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.
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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: 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.
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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: 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 Navier-Stokes CFD solver. A full 3-D RANS approach in a moving reference frame is used to model the flow. By employing periodic boundary conditions, one-third of the flow-field is analyzed and the output is replicated to other sectors. Following validation of the computation with an experimental study, the flow fields and particle paths for the case of uniform and sheared incoming flows...
Show moreThe objective of this thesis is to analyze the flow past an ocean current turbine using a finite volume Navier-Stokes CFD solver. A full 3-D RANS approach in a moving reference frame is used to model the flow. By employing periodic boundary conditions, one-third of the flow-field is analyzed and the output is replicated to other sectors. Following validation of the computation with an experimental study, the flow fields and particle paths for the case of uniform and sheared incoming flows past a generic turbine with various blade pitch angles are evaluated and analyzed. Flow field and wake expansion are visualized. Eddy viscosity effects and its dependence on flow field conditions are investigated.
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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: Emission characteristics of a liquid spray sudden expansion combustor using computational fluid dynamics.
Creator: Rodriguez, Daniel, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: A sudden expansion combustor (SUE) is analyzed using computation fluid dynamics (CFD). CO emissions and NOx emissions are computed for various operating conditions of the SUE combustor using a can type and an annular type geometrical configurations. The goal of this thesis is to see if the SUE combustor is a viable alternative to conventional combustors which utilize swirlers. It is found that for the can type combustor the NOx emissions were quite low compared to other combustor types but...
Show moreA sudden expansion combustor (SUE) is analyzed using computation fluid dynamics (CFD). CO emissions and NOx emissions are computed for various operating conditions of the SUE combustor using a can type and an annular type geometrical configurations. The goal of this thesis is to see if the SUE combustor is a viable alternative to conventional combustors which utilize swirlers. It is found that for the can type combustor the NOx emissions were quite low compared to other combustor types but the CO emissions were fairly high. The annular combustor shows better CO emissions compared to the can type, but the CO emissions are still high compared to other combustors. Emissions can be improved by providing better mixing in the primary combustion zone. The SUE combustor design needs to be further refined in order for it to be a viable alternative to conventional combustors with swirlers.
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Date Issued: 2013
PURL: http://purl.flvc.org/fcla/dt/3362574
Subject Headings: Fluid dynamics, Data processing, Fluid dynamics, Mathematical models, Computational fluid dynamics, Diffusers, Fluid dynamics
Format: Document (PDF)

Title: Evaluation of motion compensated ADV measurements for quantifying velocity fluctuations.
Creator: Lovenbury, James William., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: This study assesses the viability of using a towfish mounted ADV for quantifying water velocity fluctuations in the Florida Current relevant to ocean current turbine performance. For this study a motion compensated ADV is operated in a test flume. Water velocity fluctuations are generated by a 1.3 cm pipe suspended in front of the ADV at relative current speeds of 0.9 m/s and 0.15 m/s, giving Reynolds numbers on the order of 1000. ADV pitching motion of +/- 2.5 [degree] at 0.3 Hz and a heave...
Show moreThis study assesses the viability of using a towfish mounted ADV for quantifying water velocity fluctuations in the Florida Current relevant to ocean current turbine performance. For this study a motion compensated ADV is operated in a test flume. Water velocity fluctuations are generated by a 1.3 cm pipe suspended in front of the ADV at relative current speeds of 0.9 m/s and 0.15 m/s, giving Reynolds numbers on the order of 1000. ADV pitching motion of +/- 2.5 [degree] at 0.3 Hz and a heave motion of 0.3 m amplitude at 0.2 Hz are utilized to evaluate the motion compensation approach. The results show correction for motion provides up to an order of magnitude reduction in turbulent kinetic energy at frequencies of motion while the IMU is found to generate 2% error at 1/30 Hz and 9% error at 1/60 Hz in turbulence intensity.
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Date Issued: 2013
PURL: http://purl.flvc.org/fcla/dt/3362482
Subject Headings: Motion control systems, Fluid dynamic measurements, Fluid mechanics, Mathematical models, Analysis of covariance
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.
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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: 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 finite-aspect 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.
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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: Internal waves on a continental shelf.
Creator: Jagannathan, Arjun., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: In this thesis, a 2D CHebyshev spectral domain decomposition method is developed for simulating the generation and propagation of internal waves over a topography. While the problem of stratified flow over topography is by no means a new one, many aspects of internal wave generation and breaking are still poorly understood. This thesis aims to reproduce certain observed features of internal waves by using a Chebyshev collation method in both spatial directions. The numerical model solves the...
Show moreIn this thesis, a 2D CHebyshev spectral domain decomposition method is developed for simulating the generation and propagation of internal waves over a topography. While the problem of stratified flow over topography is by no means a new one, many aspects of internal wave generation and breaking are still poorly understood. This thesis aims to reproduce certain observed features of internal waves by using a Chebyshev collation method in both spatial directions. The numerical model solves the inviscid, incomprehensible, fully non-linear, non-hydrostatic Boussinesq equations in the vorticity-streamfunction formulation. A number of important features of internal waves over topography are captured with the present model, including the onset of wave-breaking at sub-critical Froude numbers, up to the point of overturning of the pycnoclines. Density contours and wave spectra are presented for different combinations of Froude numbers, stratifications and topographic slope.
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Date Issued: 2012
PURL: http://purl.flvc.org/FAU/3358549
Subject Headings: Engineering geology, Mathematical models, Chebyshev polynomials, Fluid dynamics, Continuum mechanics, Spectral theory (Mathematics)
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 Time-Frequency 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 Time-Frequency Analysis is required. The thesis also includes the development of two LabVIEW models. The first model combines the advanced methods for on-line condition monitoring. The second model performs the modal analysis to find the resonance frequencies of the subsystems of the turbine. The dynamic modeling of the turbine using Finite Element Analysis is used to estimate the baseline of vibration signals in sensors locations under normal operating conditions of the turbine. All this information is necessary to perform the vibration condition monitoring of the turbine.
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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: Model analysis of a mooring system for an ocean current turbine testing platform.
Creator: Cribbs, Allison Rose., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: In response to Florida's growing energy needs and drive to develop renewable power, Florida Atlantic Universitys Center for Ocean Energy Technology (COET) plans to moor a 20 kW test turbine in the Florida Current. No permanent mooring systems for deepwater hydrokinetic turbines have been constructed and deployed, therefore little if anything is known about the performance of these moorings. To investigate this proposed mooring system, a numeric model is developed and then used to predict the...
Show moreIn response to Florida's growing energy needs and drive to develop renewable power, Florida Atlantic Universitys Center for Ocean Energy Technology (COET) plans to moor a 20 kW test turbine in the Florida Current. No permanent mooring systems for deepwater hydrokinetic turbines have been constructed and deployed, therefore little if anything is known about the performance of these moorings. To investigate this proposed mooring system, a numeric model is developed and then used to predict the static and dynamic behavior of the mooring system and attachments. The model has been created in OrcaFlex and includes two surface buoys and an operating turbine. Anchor chain at the end of the mooring line develops a catenary, providing compliance. Wind, wave, and current models are used to represent the environmental conditions the system is expected to experience and model the dynamic effects on the system. The model is then used to analyze various components of the system. The results identify that a mooring attachment point 1.25 m forward of the center of gravity on the mooring buoy is ideal, and that the OCDP and turbine tether lengths should be no shorter than 25 and 44 m, respectively. Analysis performed for the full system identify that the addition of the floats decreases the tension at the MTB attachment location by 26.5 to 29.5% for minimum current, and 0.10 to 0.31% for maximum current conditions.
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Date Issued: 2010
PURL: http://purl.flvc.org/FAU/2974432
Subject Headings: Marine turbines, Mathematical models, Structural dynamics, Rotors, Design and construction, Offshore structures, Testing
Format: Document (PDF)

Title: Modeling of linear induction machines for analysis and control.
Creator: Sinisterra, Armando Jose, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: In this thesis, the analysis of the dynamic response of a Linear Induction Motor as an electromechanical system is done, accounting for all the governing equations implied in the process which are used to develop the corresponding simulation models. Once this model is presented, a feedback control system is implemented in order to analyze the controlled response of the motor, considering the applications and conditions analogue to aircraft launcher systems. Also a comparison between the...
Show moreIn this thesis, the analysis of the dynamic response of a Linear Induction Motor as an electromechanical system is done, accounting for all the governing equations implied in the process which are used to develop the corresponding simulation models. Once this model is presented, a feedback control system is implemented in order to analyze the controlled response of the motor, considering the applications and conditions analogue to aircraft launcher systems. Also a comparison between the Linear and Rotary induction motors describing the differences, similarities and equivalences will be developed.
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Date Issued: 2011
PURL: http://purl.flvc.org/FAU/3172944
Subject Headings: Electric motors, Induction, Mathematical models, Electric propulsion, Control theory
Format: Document (PDF)

Title: Noise radiation from small steps and cubic roughness elements in turbulent boundary layer flow.
Creator: Bryan, Benjamin Skyler, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Ji and Wang (2010) propose that the dominant source of sound from a forward facing step is the stream wise dipole on the face of the step and that sources acting normal to the flow are negligible. Sound radiation normal to flow of forward facing steps has been measured in wind tunnel experiments previously by Farabee and Casarella (1986, 1991) and Catlett (2010). A method for evaluating sound radiation from surface roughness proposed in Glegg and Devenport (2009) has been adapted and applied...
Show moreJi and Wang (2010) propose that the dominant source of sound from a forward facing step is the stream wise dipole on the face of the step and that sources acting normal to the flow are negligible. Sound radiation normal to flow of forward facing steps has been measured in wind tunnel experiments previously by Farabee and Casarella (1986, 1991) and Catlett (2010). A method for evaluating sound radiation from surface roughness proposed in Glegg and Devenport (2009) has been adapted and applied to flow over a forward facing step which addresses the sound normal to the flow that was previously unaccounted for. Far-field radiation predictions based on this method have been compared with wind tunnel measurements and show good agreement. A second method which evaluates the forcing from a vortex convected past surface roughness using RANS calculations and potential flow information is also evaluated.
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Date Issued: 2012
PURL: http://purl.flvc.org/FAU/3358330
Subject Headings: Turbulence, Mathematical models, Aerodynamic noise, Fluid-structure interaction, Structural dynamics, Acoustic models, Computational fluid dynamcs
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.
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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)

Fluid dynamics (12)	+ -
Marine turbines (11)	+ -
Structural dynamics (8)	+ -
Design and construction (6)	+ -
Testing (5)	+ -

Turbines (4)	+ -
Automatic control (3)	+ -
Composite materials (3)	+ -
Computational fluid dynamics (3)	+ -
Fluid mechanics (3)	+ -
Oceanographic submersibles (3)	+ -
Rotors (3)	+ -
Turbulence (3)	+ -
Underwater acoustics (3)	+ -
Vibration (3)	+ -
Acoustical engineering (2)	+ -
Blades (2)	+ -
Computer simulation (2)	+ -
Electromagnetic measurements (2)	+ -
Fluctuations (Physics) (2)	+ -
Forecasting (2)	+ -
Heat exchangers (2)	+ -
Measurement (2)	+ -
Water currents (2)	+ -
Acoustic models (1)	+ -
Aerodynamic noise (1)	+ -
Aerodynamics (1)	+ -
Airplanes (1)	+ -
Analysis of covariance (1)	+ -

College of Engineering and Computer Science (28)	+ -
Akram, Mohammad Wasim (1)	+ -
Asseff, Nicholas S. (1)	+ -
Blanc, Jean-Baptiste. (1)	+ -
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