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Title: Concrete diffusivity and its correlation with chloride deposition rate on concrete exposed to marine environments.
Creator: Echevarria, Victor Anthony., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The aim of this study was to investigate the diffusion of chloride ions into concrete samples that were exposed in scenarios that simulate the splash, tidal, atmospheric, and immersed portions of a marine structure. To study the atmospheric deposition, the project also investigated the relationship between chloride ion deposition on the wet candle and its accumulation into concrete samples. Results from the wet candle experiment indicated that between 2% and 45% of the chlorides deposited per...
Show moreThe aim of this study was to investigate the diffusion of chloride ions into concrete samples that were exposed in scenarios that simulate the splash, tidal, atmospheric, and immersed portions of a marine structure. To study the atmospheric deposition, the project also investigated the relationship between chloride ion deposition on the wet candle and its accumulation into concrete samples. Results from the wet candle experiment indicated that between 2% and 45% of the chlorides deposited per square meter of exposed area could be found within the concrete samples. After 6 months, slag G1a blocks showed the most resistance to chloride penetration in the tidal and splash simulations. After 10 months of exposure, fly ash samples had the slowest rates of diffusion in the tidal simulation while the fly ash + silica fume samples and the slag samples measured similar rates of diffusion within the tidal zone. After 90 days of curing, cylinders composed of 20% fly ash & 8% silica fume measured the highest average resistivity values and were found to be less vulnerable to chloride ion penetration than the 20% fly ash and the 50% slag concrete through rapid migration tests.
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Date Issued: 2012
PURL: http://purl.flvc.org/FAU/3358557
Subject Headings: Reinforced concrete, Construction, Corrosion, Composite reinforced concrete, Corrosion, Testing, Concrete, Fluid dynamics, Concrete, Chemical resistance, Chlorides, Diffusion rate
Format: Document (PDF)

Title: Farfield modeling of the Boynton Inlet plume using sulfur hexafluoride as tracer.
Creator: Pire-Schmidt, Joaquin., College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
Abstract/Description: The analysis and modeling of the coastal farfield behavior of inlet discharge plumes is the key to understanding the fate of pollutants discharged into the ocean. These plumes disperse in chaotic and unpredictable patterns. Theoretical models are based on the average conditions and calibrated to the results of tracer studies. Data and models for freshwater discharges in coastal ocean systems are limited because of the lack of adequate tracers. On February, 2007, a tracer study was conducted...
Show moreThe analysis and modeling of the coastal farfield behavior of inlet discharge plumes is the key to understanding the fate of pollutants discharged into the ocean. These plumes disperse in chaotic and unpredictable patterns. Theoretical models are based on the average conditions and calibrated to the results of tracer studies. Data and models for freshwater discharges in coastal ocean systems are limited because of the lack of adequate tracers. On February, 2007, a tracer study was conducted on the Boynton Inlet, Florida, using sulfur hexafluoride (SF6) tracer. The objective of this study is to provide methods of analysis for the sample data collected during the experiment. The detected tracer concentrated in a bolus that migrated north of the inlet at velocities lower than predicted by the current data. The plume was successfully modeled with a Gaussian plume model, with 90% of the SF6 predictions having less than 4.6 pptr error.
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Date Issued: 2009
PURL: http://purl.flvc.org/FAU/186771
Subject Headings: Plumes (Fluid dynamics), Water, Pollution, Sedimentation and deposition, Environmental aspects, Pollution, Mathematical models
Format: Document (PDF)

Title: Transport and dispersion of fire extinguishing agents downstream from clutter elements of aircraft engine nacelles.
Creator: Zbeeb, Khaled., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The combination of highly turbulent airflow, flammable fluids, and numerous ignition sources makes aircraft engine nacelles a difficult fire zone to protect. Better understanding of nacelle air flow and how it influences the spread of fires and fire extinguishing agents is needed to improve the efficiency of fire suppression. The first objective was to establish a CFD model for a flow field test section to analyze the transport and dispersion of fire extinguishing agents in the presence of...
Show moreThe combination of highly turbulent airflow, flammable fluids, and numerous ignition sources makes aircraft engine nacelles a difficult fire zone to protect. Better understanding of nacelle air flow and how it influences the spread of fires and fire extinguishing agents is needed to improve the efficiency of fire suppression. The first objective was to establish a CFD model for a flow field test section to analyze the transport and dispersion of fire extinguishing agents in the presence of various clutter elements. To validate the use of the CFD model, the simulation results of the CFD model were compared to the experimental data and they show an agreement with the experimental data. The second objective was to present parametric studies to show the effects of the coflow speed, turbulence intensity and agent droplet size on the transport and dispersion of the agent particles downstream from the clutter elements.
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Date Issued: 2009
PURL: http://purl.flvc.org/FAU/186687
Subject Headings: Airplanes, Nacelles, Safety measures, Airplanes, Fires and fire prevention, Fire extinguishing agents, Testing, Airplanes, Fluid dynamics, Mathematical models
Format: Document (PDF)

Title: Wave Ship Interaction in Transforming Seas.
Creator: Gong, Fuxian, Dhanak, Manhar R., Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: In near-shore transforming seas, as waves approach the shoreline, wave shoaling and sometimes wave breaking take place due to the decreasing water depth. When a ship advances through the transforming seas, the ship body and waves interact with each other substantially and can lead to unknown motions of the ship hull. The physical process of how the wave transforms in the surf zone and how the vehicle actually behaves when it passes through the transforming seas is a complicated issue that...
Show moreIn near-shore transforming seas, as waves approach the shoreline, wave shoaling and sometimes wave breaking take place due to the decreasing water depth. When a ship advances through the transforming seas, the ship body and waves interact with each other substantially and can lead to unknown motions of the ship hull. The physical process of how the wave transforms in the surf zone and how the vehicle actually behaves when it passes through the transforming seas is a complicated issue that triggers considerable research interest. The goal of my research is to characterize the dynamics of a high-speed surface ship model in transforming seas through a parametric numerical study of the shipwave interactions. In this study, the vehicle of interest is a surface effect ship (SES) and we aim to contribute to developing a methodology for simulating the transforming wave environment, including wave breaking, and its interactions with the SES. The thesis work uses a commercial software package ANSYS Fluent to generate numerical waves and model the interface between water and air using the volume of fluid (VoF) method. A ship motion solver and the dynamic mesh are used to enable the modeled ship to perform three degree-of-freedom (DoF) motion and the near-region of the ship hull to deform as well as re-mesh. Non-conformal meshes with hybrid compositions of different cell types and various grid sizes are used in the simulations for different purposes. Five user-defined functions (UDFs) are dynamically linked with the flow solver to incorporates ship/grid motions, wave damping and output of the numerical results. A series of steps were taken sequentially: 1) validation for ship motions including simulation of a static Wigley hull under steady flows to compare against previous experimental results by other researchers, and the comparison between the static SES model under steady flows and the moving SES model advancing in the calm water; 2) study of the ship with 3 DoF advancing in calm water of both constant depth and varying depth; 3) validation for numerical waves, including predictions of numerically progressive waves in both a regular tank and a tank with a sloped fringing reef to compare with theoretical and experimental results, respectively; 4) investigation of the transforming characteristics of the wave traveling over the sloped fringing reef, which mimics the near-shore wave environment and a study of the dynamics of the SES through transforming waves. We find that the flow solver used in this study reliably models the wave profiles along the ship hull. The comparison between a static SES in a current and a moving SES in calm water at the same Froude number shows that although the velocity fields around the vehicle are significantly different, the wave profiles inside and outside the rigid cushion of the vehicle are similar and the resistance force experienced by the vehicle in the two scenarios agree well over time. We conducted five numerical simulations of the vehicle traveling from shallow water to deep water across the transition zone for different Froude numbers. From the results, we find that as the Froude number increases, the wave resistance force on the vehicle becomes larger in both shallow water and deep water. In addition, the overall mean resistance force experienced by the vehicle over the whole trip increases with the Froude number. Statistical analysis of the wave motions suggests that the energy flux decreases dramatically in the onshore direction as the waves break. The more severe the wave-breaking process, the greater the decrease in energy flux. Both the increase of Froude number and the wave steepness apparently increase the resistance force on the vehicle in the shallow water. This thesis work captures the impact of the transforming characteristics of the waves and closely replicates the behavior of how waves interact with a ship in transforming seas through numerical modeling and simulation.
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Date Issued: 2017
PURL: http://purl.flvc.org/fau/fd/FA00004916, http://purl.flvc.org/fau/fd/FA00004916
Subject Headings: Hydrodynamics--Mathematical models., Fluid dynamics--Mathematical models., Ocean waves--Measurement., Water waves--Measurement., Coastal engineering.
Format: Document (PDF)

Title: Some corrosion problems associated with underwater turbines.
Creator: Miglis, Yohann., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: This thesis deals with corrosion problems of underwater turbines in marine environment. The effect of a tensile stress on the uniform corrosion rate of a metal bar is studied, and an analytical model predicting the time of service of a bar under a tensile load in a corrosive environment is proposed. Stress corrosion relationships are provided for different type of alloys, and different types of relationships. Dolinskii's and Gutman's models are studied and extended to a general order...
Show moreThis thesis deals with corrosion problems of underwater turbines in marine environment. The effect of a tensile stress on the uniform corrosion rate of a metal bar is studied, and an analytical model predicting the time of service of a bar under a tensile load in a corrosive environment is proposed. Stress corrosion relationships are provided for different type of alloys, and different types of relationships. Dolinskii's and Gutman's models are studied and extended to a general order polynomial, along with a Least Square and Spline Interpolation of the experimental data. In a second part, the effect of the passive film, delaying the initiation of the corrosion process, is studied. Finally, an algorithm predicting the time of service of a cracked bar is provided, using the stress corrosion assumption, along with a validation using experimental data.
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Date Issued: 2012
PURL: http://purl.flvc.org/FAU/3342238
Subject Headings: Turbines, Stress corrosion, Testing, Computational fluid dynamics, Stress corrosion, Fracture mechanics, Measurement, Alloys, Stress corrosion, Testing, Alloys, Corrosion fatigue, Testing
Format: Document (PDF)

Title: A STUDY OF THE EFFECT OF FLOW PARAMETERS ON THE CATHODIC PROTECTION OF A STEEL PLATE IN NATURAL SEAWATER.
Creator: MCCABE, KEVIN MICHAEL., Florida Atlantic University, Smith, Samuel W., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The influence of hydrodynamic parameters and cathodic polarization on the formation of calcareous deposits on a steel plate in flowing seawater is investigated. Current density variations on the plate are determined for a combination of applied potentials and seawater velocities. Equations are developed to relate the cathodic current density distribution to variations in hydrodynamic and diffusional boundary layer thickness along the plate for laminar and turbulent flow regimes. A comparison...
Show moreThe influence of hydrodynamic parameters and cathodic polarization on the formation of calcareous deposits on a steel plate in flowing seawater is investigated. Current density variations on the plate are determined for a combination of applied potentials and seawater velocities. Equations are developed to relate the cathodic current density distribution to variations in hydrodynamic and diffusional boundary layer thickness along the plate for laminar and turbulent flow regimes. A comparison of experimental current densities on a bare plate to that predicted by theory is examined. Effects of flow on the formation and properties of calcareous deposits are discussed in light of recent developments in marine cathodic protection.
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Date Issued: 1984
PURL: http://purl.flvc.org/fcla/dt/14192
Subject Headings: Plates, Iron and steel--Cathodic protection, Carbon steel--Corrosion, Plates, Iron and steel--Fluid dynamics, Cathodic protection
Format: Document (PDF)

Title: Design and Deployment Analysis of Morphing Ocean Structure.
Creator: Li, Yanjun, Su, Tsung-Chow, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: As humans explore greater depths of Earth’s oceans, there is a growing need for the installation of subsea structures. 71% of the earth’s surface is ocean but there are limitations inherent in current detection instruments for marine applications leading to the need for the development of underwater platforms that allow research of deeper subsea areas. Several underwater platforms including Autonomous Underwater Vehicles (AUVs), Remote Operated Vehicles (ROVs), and wave gliders enable more...
Show moreAs humans explore greater depths of Earth’s oceans, there is a growing need for the installation of subsea structures. 71% of the earth’s surface is ocean but there are limitations inherent in current detection instruments for marine applications leading to the need for the development of underwater platforms that allow research of deeper subsea areas. Several underwater platforms including Autonomous Underwater Vehicles (AUVs), Remote Operated Vehicles (ROVs), and wave gliders enable more efficient deployment of marine structures. Deployable structures are able to be compacted and transported via AUV to their destination then morph into their final form upon arrival. They are a lightweight, compact solution. The wrapped package includes the deployable structure, underwater pump, and other necessary instruments, and the entire package is able to meet the payload capability requirements. Upon inflation, these structures can morph into final shapes that are a hundred times larger than their original volume, which extends the detection range and also provides long-term observation capabilities. This dissertation reviews underwater platforms, underwater acoustics, imaging sensors, and inflatable structure applications then proposes potential applications for the inflatable structures. Based on the proposed applications, a conceptual design of an underwater tubular structure is developed and initial prototypes are built for the study of the mechanics of inflatable tubes. Numerical approaches for the inflation process and bending loading are developed to predict the inflatable tubular behavior during the structure’s morphing process and under different loading conditions. The material properties are defined based on tensile tests. The numerical results are compared with and verified by experimental data. The methods used in this research provide a solution for underwater inflatable structure design and analysis. Several ocean morphing structures are proposed based on the inflatable tube analysis.
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Date Issued: 2016
PURL: http://purl.flvc.org/fau/fd/FA00004752, http://purl.flvc.org/fau/fd/FA00004752
Subject Headings: Air-supported structures--Design and construction., Remote submersibles--Design and construction., Tensile architecture., Fluid mechanics., Structural dynamics., Ocean engineering., Adaptive control systems.
Format: Document (PDF)

Title: Investigation of marine waterjet inlets during turning maneuvers.
Creator: Duerr, Phillip S., von Ellenrieder, Karl, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Numerical simulations of waterjet inlets have been conducted in order to understand inlet performance during ship turning maneuvers. During turning maneuvers waterjet systems may experience low efficiency, cavitation, vibration, and noise. This study found that during turns less energy arrived at the waterjet pump relative to operating straight ahead, and that the flow field at the entrance of the waterjet pump exhibited a region of both low pressure and low axial velocity. The primary reason...
Show moreNumerical simulations of waterjet inlets have been conducted in order to understand inlet performance during ship turning maneuvers. During turning maneuvers waterjet systems may experience low efficiency, cavitation, vibration, and noise. This study found that during turns less energy arrived at the waterjet pump relative to operating straight ahead, and that the flow field at the entrance of the waterjet pump exhibited a region of both low pressure and low axial velocity. The primary reason for the change in pump inflow uniformity is due to a streamwise vortex. In oblique inflow the hull boundary layer separates when entering the inlet and wraps up forming the streamwise vortex. These changes in pump inflow during turning maneuvers will result in increased unsteady loading of the pump rotor and early onset of pump rotor cavitation.
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Date Issued: 2015
PURL: http://purl.flvc.org/fau/fd/FA00004364, http://purl.flvc.org/fau/fd/FA00004364
Subject Headings: Fluid dynamics, Ships--Hydrodynamics, Ships--Maneuverability--Simulation methods, Ship handling--Simulation methods, Ship propulsion, Stability of ships, Oceanographic instruments--Evaluation
Format: Document (PDF)

Title: Recovering Titanium Dioxide (TiO2) after its Use to Treat Leachate for Reuse on Future Leachate Flows.
Creator: Coffman, Neil, Meeroff, Daniel E., Florida Atlantic University, College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
Abstract/Description: This thesis was about finding a recovery method for TiO2, using a TiO2 recovery technology, which was high enough to be economical ($10 - $15 per 1,000 gallons) to be adopted by wastewater treatment plants. When comparing recovery technologies, the top three which were investigated further through experimentation were a centrifuge, sedimentation tank, and microfilter membrane. Upon experimentation and research, the TiO2 recovery efficiencies of these technologies were 99.5%, 92.5%, and 96.3%,...
Show moreThis thesis was about finding a recovery method for TiO2, using a TiO2 recovery technology, which was high enough to be economical ($10 - $15 per 1,000 gallons) to be adopted by wastewater treatment plants. When comparing recovery technologies, the top three which were investigated further through experimentation were a centrifuge, sedimentation tank, and microfilter membrane. Upon experimentation and research, the TiO2 recovery efficiencies of these technologies were 99.5%, 92.5%, and 96.3%, respectively. When doing economic analysis on these technologies comparing TiO2 efficiencies and capital and operational costs, the centrifuge was the most preferred economic option. Also, its cost did were in the economical range ($10 - $15/1,000 gallons) which makes even this technology economical. Besides that, important and valuable information about TiO2: settling behavior, particle size and zeta potential, interactions with COD, and filter operations (particle characterization) were discovered for future research and future testing on this issue.
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Date Issued: 2015
PURL: http://purl.flvc.org/fau/fd/FA00004490, http://purl.flvc.org/fau/fd/FA00004490
Subject Headings: Environmental chemistry, Environmental engineering, Fluid dynamics, Microfluidic devices, Sewage disposal plants -- Management, Solution (Chemistry), Titanium dioxide -- Environmental aspects, Titanium dioxide -- Industrial applications
Format: Document (PDF)

Title: Subjecting the CHIMERA supernova code to two hydrodynamic test problems, (i) Riemann problem and (ii) Point blast explosion.
Creator: Ahsan, Abu Salah M., Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: A Shock wave as represented by the Riemann problem and a Point-blast explosion are two key phenomena involved in a supernova explosion. Any hydrocode used to simulate supernovae should be subjected to tests consisting of the Riemann problem and the Point-blast explosion. L. I. Sedov's solution of Point-blast explosion and Gary A. Sod's solution of a Riemann problem have been re-derived here from one dimensional fluid dynamics equations . Both these problems have been solved by using the idea...
Show moreA Shock wave as represented by the Riemann problem and a Point-blast explosion are two key phenomena involved in a supernova explosion. Any hydrocode used to simulate supernovae should be subjected to tests consisting of the Riemann problem and the Point-blast explosion. L. I. Sedov's solution of Point-blast explosion and Gary A. Sod's solution of a Riemann problem have been re-derived here from one dimensional fluid dynamics equations . Both these problems have been solved by using the idea of Self-similarity and Dimensional analysis. The main focus of my research was to subject the CHIMERA supernova code to these two hydrodynamic tests. Results of CHIMERA code for both the blast wave and Riemann problem have then been tested by comparing with the results of the analytic solution.
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Date Issued: 2008
PURL: http://purl.flvc.org/FAU/172665
Subject Headings: Mathematical physics, Continuum mechanics, Number theory, Supernovae, Data processing, Shock waves, Fluid dynamics
Format: Document (PDF)

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