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A Study of the Underwater Acoustic Propagation in a Turning Basin Modeled as a Three-Dimensional Duct Closed at One End Using the Method of Images
Title
A Study of the Underwater Acoustic Propagation in a Turning Basin Modeled as a Three-Dimensional Duct Closed at One End Using the Method of Images.
Creator
Staska, Matthew D., Beaujean, Pierre-Philippe, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
A computer-efficient model of the underwater acoustic propagation m a shallow, three-dimensional duct closed at one end has been developed using the method of images. Presented in this research is the development of this three-dimensional method of images analysis for a rectangular duct. Using this analysis, a model of the impulse response of the acoustic channel is constructed. Also presented in this work is the actual impulse response collected during field experimentation in the south...
Show moreA computer-efficient model of the underwater acoustic propagation m a shallow, three-dimensional duct closed at one end has been developed using the method of images. Presented in this research is the development of this three-dimensional method of images analysis for a rectangular duct. Using this analysis, a model of the impulse response of the acoustic channel is constructed. Also presented in this work is the actual impulse response collected during field experimentation in the south turning basin of Port Everglades in Fort Lauderdale, Florida. The results demonstrate that the impulse response is modeled with a relative echo magnitude error of 1.62 dB at worst, and a relative echo location error varying between 0% and 4% when averaged across multiple measurements and sensor locations.
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Date Issued
2007
PURL
http://purl.flvc.org/fau/fd/FA00012557
Subject Headings
Underwater acoustics--Measurement, Wave motion, Theory of, Wave equation--Numerical solutions, Sound-waves--Transmission--Mathematical models
Format
Document (PDF)
Dynamic analysis of single- and multi-module platforms in waves
Title
Dynamic analysis of single- and multi-module platforms in waves.
Creator
Kling, Kaylie Ann., Florida Atlantic University, Ananthakrishnan, Palaniswamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
The response of single- and multi-module floating platforms to surface waves is investigated theoretically. Wave exciting forces are computed using methods based on the Morrison equation and Froude-Krylov hypothesis. The radiation forces are obtained from experimental results of Vugt and where possible diffraction forces using the Haskind reciprocity relation. Heave and pitch response of a one-module platform and hinge-connected two-module platform are determined by integrating the...
Show moreThe response of single- and multi-module floating platforms to surface waves is investigated theoretically. Wave exciting forces are computed using methods based on the Morrison equation and Froude-Krylov hypothesis. The radiation forces are obtained from experimental results of Vugt and where possible diffraction forces using the Haskind reciprocity relation. Heave and pitch response of a one-module platform and hinge-connected two-module platform are determined by integrating the corresponding equations of rigid-body motion. A structural dynamic analysis is also carried out using the Green's function method to determine the elastic flexural response of the platform to waves. The results are compared with the experimental and numerical findings of others. The thesis contributes to a better understanding of rigid-body and elastic response of large ocean platforms subject to wave forces. The methodology is computationally less intensive and therefore can be effectively used for the design of platforms and the validation of numerical algorithms.
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Date Issued
2006
PURL
http://purl.flvc.org/fcla/dt/13399
Subject Headings
Ocean engineering, Wave motion, Theory of, Water waves--Mathematical models, Drilling platforms, Extreme value theory
Format
Document (PDF)
Dynamic positioning and motion mitigation of a scaled sea basing platform
Title
Dynamic positioning and motion mitigation of a scaled sea basing platform.
Creator
Marikle, Sean P., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
A 6-Degree Of Freedom (DOF) numeric model and computer simulation along with the 1/10th scale physical model of the Rapidly Deployable Stable Platform (RDSP) are being developed at Florida Atlantic University in response to military needs for ocean platforms with improved sea keeping characteristics. The RDSP is a self deployable spar platform with two distinct modes of operation enabling long distance transit and superior seakeeping. The focus of this research is the development of a Dynamic...
Show moreA 6-Degree Of Freedom (DOF) numeric model and computer simulation along with the 1/10th scale physical model of the Rapidly Deployable Stable Platform (RDSP) are being developed at Florida Atlantic University in response to military needs for ocean platforms with improved sea keeping characteristics. The RDSP is a self deployable spar platform with two distinct modes of operation enabling long distance transit and superior seakeeping. The focus of this research is the development of a Dynamic Position (DP) and motion mitigation system for the RDSP. This will be accomplished though the validation of the mathematical simulation, development of a novel propulsion system, and implementation of a PID controller. The result of this research is an assessment of the response characteristics of the RDSP that quantifies the performance of the propulsion system coupled with active control providing a solid basis for further controller development and operational testing.
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Date Issued
2009
PURL
http://purl.flvc.org/FAU/228767
Subject Headings
Inertial navigation systems, Mobile offshore structures, Design and construction, Wave motion, Theory of, Offshore structures, Dynamics, Feedback control systems
Format
Document (PDF)
Effect of wind on near-shore breaking waves
Title
Effect of wind on near-shore breaking waves.
Creator
Schaffer, Faydra., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
The aim of this project is to identify the effect of wind on near-shore breaking waves. A breaking wave was created using a simulated beach slope configuration. Testing was done on two different beach slope configurations. The effect of offshore winds of varying speeds was considered. Waves of various frequencies and heights were considered. A parametric study was carried out. The experiments took place in the Hydrodynamics lab at FAU Boca Raton campus. The experimental data validates the...
Show moreThe aim of this project is to identify the effect of wind on near-shore breaking waves. A breaking wave was created using a simulated beach slope configuration. Testing was done on two different beach slope configurations. The effect of offshore winds of varying speeds was considered. Waves of various frequencies and heights were considered. A parametric study was carried out. The experiments took place in the Hydrodynamics lab at FAU Boca Raton campus. The experimental data validates the knowledge we currently know about breaking waves. Offshore winds effect is known to increase the breaking height of a plunging wave, while also decreasing the breaking water depth, causing the wave to break further inland. Offshore winds cause spilling waves to react more like plunging waves, therefore increasing the height of the spilling wave while consequently decreasing the breaking water depth.
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Date Issued
2010
PURL
http://purl.flvc.org/FAU/2979378
Subject Headings
Wave motion, Theory of, Ocean waves, Climatology, Computational fluid dynamics
Format
Document (PDF)
Hydrodynamic analysis of underwater bodies for efficient station keeping in shallow waters with surface waves
Title
Hydrodynamic analysis of underwater bodies for efficient station keeping in shallow waters with surface waves.
Creator
Bradley, Matthew, Ananthakrishnan, Palaniswamy, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
To determine the effect of body shape on the response of underwater vehicles to surface waves in shallow water, the wave radiation hydrodynamic forces are evaluated for a family of (i) prolate spheroidal hull forms and (ii) cylindrical bodies with hemispherical nose and conical tail sections by systematically varying the geometric parameters but keeping displacement constant. The added-mass and wave damping coefficients are determined using a frequency-domain, simple-source based boundary...
Show moreTo determine the effect of body shape on the response of underwater vehicles to surface waves in shallow water, the wave radiation hydrodynamic forces are evaluated for a family of (i) prolate spheroidal hull forms and (ii) cylindrical bodies with hemispherical nose and conical tail sections by systematically varying the geometric parameters but keeping displacement constant. The added-mass and wave damping coefficients are determined using a frequency-domain, simple-source based boundary integral method. Results are obtained for a range of wave frequencies and depths of vehicle submergence all for a fixed water depth of 10 m. With the wave exciting force and moment determined using the Froude-Krylov theory, the response transfer functions for heave and pitch are then determined. The heave and pitch response spectra in actual littoral seas are then determined with the sea state modeled using TMA spectral relations. Results show that vehicle slenderness is a key factor affecting the hydrodynamic coefficients and response. The results show two characteristics that increase the radiation hydrodynamic forces corresponding to heave and pitch motions: namely, vehicle length and further-away from mid-vehicle location of the body shoulder. The opposite is true for the oscillatory surge motion. By utilizing these observed characteristics, one can design the lines for maximum radiation forces and consequently minimum hull response for the critical modes of rigid-body motion in given waters and vehicle missions. In the studies carried out in the thesis, a hull with a long parallel middle body with hemispherical nose and conical tail sections has better heave and pitch response characteristics compared prolate spheroid geometry of same volume. The methodology developed herein, which is computationally efficient, can be used to determine optimal hull geometry for minimal passive vehicle response in a given sea.
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Date Issued
2014
PURL
http://purl.flvc.org/fau/fd/FA00004084, http://purl.flvc.org/fau/fd/FA00004084
Subject Headings
Oceanographic submersibles -- Hydrodynamics, Surface waves (Oceanography) -- Mathematical models, Wave motion, Theory of
Format
Document (PDF)
low-cost, high rate motion measurement system for an unmanned surface vehicle with underwater navigation and oceanographic applications
Title
A low-cost, high rate motion measurement system for an unmanned surface vehicle with underwater navigation and oceanographic applications.
Creator
Gelin, Chrystel., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
Standard GPS receivers are unable to provide the rate or precision required when used on a small vessel such as an Unmanned Surface Vehicles (USVs). To overcome this, the thesis presents a low cost high rate motion measurement system for an USV with underwater and oceanographic purposes. The work integrates an Inertial Measurement Unit (IMU), a GPS receiver, a flux-gate compass, a tilt sensor and develops a software package, using real time data fusion methods, for an USV to aid in the...
Show moreStandard GPS receivers are unable to provide the rate or precision required when used on a small vessel such as an Unmanned Surface Vehicles (USVs). To overcome this, the thesis presents a low cost high rate motion measurement system for an USV with underwater and oceanographic purposes. The work integrates an Inertial Measurement Unit (IMU), a GPS receiver, a flux-gate compass, a tilt sensor and develops a software package, using real time data fusion methods, for an USV to aid in the navigation and control as well as controlling an onboard Acoustic Doppler Current Profiler (ADCP).While ADCPs non-intrusively measure water flow, they suffer from the inability to discriminate between motions in the water column and self-motion. Thus, the vessel motion contamination needs to be removed to analyze the data and the system developed in this thesis provides the motion measurements and processing to accomplish this task.
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Date Issued
2010
PURL
http://purl.flvc.org/FAU/2709690
Subject Headings
Oceanographic instruments, Evaluation, Underwater navigation, Adaptive signal processing, Inertial navigation systems, Wave motion, Theory of
Format
Document (PDF)
Seakeeping response of a Surface Effect Ship in near-shore transforming seas
Title
Seakeeping response of a Surface Effect Ship in near-shore transforming seas.
Creator
Kindel, Michael., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
Scale model tests are conducted of a Surface Effect Ship in a near-shore developing sea. A beach is built and installed in a wave tank, and a wavemaker is built and installed in the same wave tank. This arrangement is used to simulate developing sea conditions and a 1:30 scale model SES is used for a series of experiments. Pitch and heave measurements are used to investigate the seakeaping response of the vessel in developing seas. The air-cushion pressure and the vessel speed are varied, and...
Show moreScale model tests are conducted of a Surface Effect Ship in a near-shore developing sea. A beach is built and installed in a wave tank, and a wavemaker is built and installed in the same wave tank. This arrangement is used to simulate developing sea conditions and a 1:30 scale model SES is used for a series of experiments. Pitch and heave measurements are used to investigate the seakeaping response of the vessel in developing seas. The air-cushion pressure and the vessel speed are varied, and the seakeeping results are compared as functions of these two parameters. The experiment results show a distinct correlation between the air-cushion pressure and the response amplitude of both pitch and heave. The results of these experiments are compared against results of a computer model of a Surface Effect Ship (SES).
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Date Issued
2012
PURL
http://purl.flvc.org/FAU/3355563
Subject Headings
Naval architecture, Fluid dynamics, Wave motion, Theory of, Ships, Hydrodynamics
Format
Document (PDF)
Spectral evaluation of motion compensated adv systems for ocean turbulence measurements
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.
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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)
System identification methodology for a wave adaptive modular unmanned surface vehicle
Title
System identification methodology for a wave adaptive modular unmanned surface vehicle.
Creator
Mask, Janine L., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
The design, implementation, and testing of an experimental setup intended to evaluate the dynamic maneuvering performance of the Wave Adaptive Modular Vessel (WAM-V) class USV12, a 3.7 meter unmanned surface vehicle (USV) is described. A comprehensive sensor package was designed, fabricated and assembled to record the vehicle's dynamic response to various control inputs. All subsystems were fabricated and installed on a test vehicle, GUSS, and full system, open-loop maneuvering tests were...
Show moreThe design, implementation, and testing of an experimental setup intended to evaluate the dynamic maneuvering performance of the Wave Adaptive Modular Vessel (WAM-V) class USV12, a 3.7 meter unmanned surface vehicle (USV) is described. A comprehensive sensor package was designed, fabricated and assembled to record the vehicle's dynamic response to various control inputs. All subsystems were fabricated and installed on a test vehicle, GUSS, and full system, open-loop maneuvering tests were conducted to show validity of data collection technique. Simulations were performed using model parameters found in the literature to create a "simulated experimental" data set, upon which system identification techniques were used to rediscover a suitable model with similar parameterization. Combined, the sensor package and the method for creating this model support future work in the design of automatic control, navigation, and guidance systems for the WAM-V USV12.
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Date Issued
2011
PURL
http://purl.flvc.org/FAU/3332720
Subject Headings
Oceanographic instruments, Evaluation, Wave motion, Theory of, Inertial navigation systems, Adaptive signal processing
Format
Document (PDF)
Test platform development for measuring surface effect ship response to wave loads
Title
Test platform development for measuring surface effect ship response to wave loads.
Creator
Kouvaras, Nicholas, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
The goal of this thesis is to develop a test platform for measuring surface effect ship (SES) response to wave loads. The platform is designed and built incorporating a self-propelled vehicle with data acquisition and navigation capabilities. Theoretical analysis is performed, various hardware and electronic parts are designed and built and software applications developed. Wave tank experiments are conducted for test platform evaluation and determination of vehicle response to a range of wave...
Show moreThe goal of this thesis is to develop a test platform for measuring surface effect ship (SES) response to wave loads. The platform is designed and built incorporating a self-propelled vehicle with data acquisition and navigation capabilities. Theoretical analysis is performed, various hardware and electronic parts are designed and built and software applications developed. Wave tank experiments are conducted for test platform evaluation and determination of vehicle response to a range of wave conditions. Furthermore, a three-dimensional model of the AIRCAT scale model SES is created. The theoretical analysis shows that the scale effects in some cases are great, so resonance phenomena cannot be observed. The experimental results clearly show that the heave, pitch and aircushion excess pressure fluctuations increase as the air-blower input level increases. The bow skirt arrangement needs improvements and further experimentation is necessary in order to draw conclusions about the wave loads applied on the skirt.
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Date Issued
2010
PURL
http://purl.flvc.org/FAU/1927307
Subject Headings
Mobile offshore structures, Design and construction, Wave motion, Theory of, Inertial navigation systems, Oceanographic instruments, Evaluation
Format
Document (PDF)