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ANALYSIS OF LIQUID IMPACT ON MOVING CONTAINERS
Title
ANALYSIS OF LIQUID IMPACT ON MOVING CONTAINERS.
Creator
KANG, SIN YOUNG., Florida Atlantic University, Su, Tsung-Chow, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
A numerical algorithm based on the Volume of Fluid technique, is used to study the impact loading of liquid sloshing in partially filled enclosed prismatic tanks subject to large amplitude excitation. A moving coordinate system fixed to the tank is introduced. Based on the Navier-Stokes equations, finite difference equations are solved. The entire flow configuration is advanced through a finite increment of time. In transporting the fluid through the mesh, an improved donor-acceptor method...
Show moreA numerical algorithm based on the Volume of Fluid technique, is used to study the impact loading of liquid sloshing in partially filled enclosed prismatic tanks subject to large amplitude excitation. A moving coordinate system fixed to the tank is introduced. Based on the Navier-Stokes equations, finite difference equations are solved. The entire flow configuration is advanced through a finite increment of time. In transporting the fluid through the mesh, an improved donor-acceptor method which takes into account surface orientation and transports trapezoidal shapes from cell to cell is used. The results obtained using the simple and improved schemes are compared. It is shown that a long time simulation can be achieved for both shallow and deep liquid sloshing.
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Date Issued
1984
PURL
http://purl.flvc.org/fcla/dt/14205
Subject Headings
Sloshing (Hydrodynamics)
Format
Document (PDF)
Application of probabilistic analogy to groundwater contamination problems
Title
Application of probabilistic analogy to groundwater contamination problems.
Creator
Qiu, Xin., Florida Atlantic University, Su, Tsung-Chow, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
This thesis addresses the groundwater contamination problem from a probabilistic point of view. The objective of this study is to obtain analytical solutions for the backward type Kolmogorov equations governing certain crucial variables in the case of a two-dimensional medium. These include the rate at which pollutants enter the protected zone and the length of time that a pollutant particle takes to travel from a given location to the boundary of the protected zone. It is assumed that the...
Show moreThis thesis addresses the groundwater contamination problem from a probabilistic point of view. The objective of this study is to obtain analytical solutions for the backward type Kolmogorov equations governing certain crucial variables in the case of a two-dimensional medium. These include the rate at which pollutants enter the protected zone and the length of time that a pollutant particle takes to travel from a given location to the boundary of the protected zone. It is assumed that the groundwater flow is horizontal and uniform, and that a protected zone is located downstream. Analytical solutions are obtained by using the techniques of Laplace transform and separation of variables. Numerical results are given for two cases, one with flow coming from a boundary which is imperious to the pollutant, and another with flow coming from infinity.
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Date Issued
1993
PURL
http://purl.flvc.org/fcla/dt/14980
Subject Headings
Groundwater--Pollution--Mathematical models, Groundwater flow--Mathematical models, Pollutants
Format
Document (PDF)
BEHAVIOR OF A SWIRLING BUOYANT TURBULENT JET IN A CROSS FLOW
Title
BEHAVIOR OF A SWIRLING BUOYANT TURBULENT JET IN A CROSS FLOW.
Creator
VISWANATHAN, SURESH., Florida Atlantic University, Su, Tsung-Chow, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
The behavior of a swirling buoyant turbulent jet in a cross flow has been studied. Dimensional analysis has been carried out to obtain asymptotic relations for the jet trajectory and dilution. Experiments were carried out to ascertain the validity of the relations obtained and to evaluate the constants arising in the analysis. While photographic observations were made to study the jet trajectory, concentration measurements were made using a light probe. Measurements of the spreading angle of...
Show moreThe behavior of a swirling buoyant turbulent jet in a cross flow has been studied. Dimensional analysis has been carried out to obtain asymptotic relations for the jet trajectory and dilution. Experiments were carried out to ascertain the validity of the relations obtained and to evaluate the constants arising in the analysis. While photographic observations were made to study the jet trajectory, concentration measurements were made using a light probe. Measurements of the spreading angle of the jet were also made. The study indicated that swirl caused an increase in spreading angle of the jet, and a great improvement in jet dilution.
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Date Issued
1986
PURL
http://purl.flvc.org/fcla/dt/14317
Subject Headings
Jets, Hydrodynamics
Format
Document (PDF)
Comparison of the Rotational Behavior of Coffee Creamer in Two Different Liquid Media
Title
Comparison of the Rotational Behavior of Coffee Creamer in Two Different Liquid Media.
Creator
Lindstedt, Erik, Sandoval, Sarel, Gavalas, Sebastian, Nguyen, Kevin, Balark, Kamanie, Su, Tsung-Chow, College of Engineering and Computer Science
Abstract/Description
The purpose of this research was to explore dispersion patterns of coffee creamer when exposed to rotating fresh water. The dispersion patterns of the creamer were observed after being both added directly to the rotating water and when having to first traverse a layer of vegetable oil. A rotating platform supporting a beaker was controlled through a power supply. The power supply was adjusted and the dispersion patterns of the creamer were observed at 2, 4, and 6 volts. When added directly,...
Show moreThe purpose of this research was to explore dispersion patterns of coffee creamer when exposed to rotating fresh water. The dispersion patterns of the creamer were observed after being both added directly to the rotating water and when having to first traverse a layer of vegetable oil. A rotating platform supporting a beaker was controlled through a power supply. The power supply was adjusted and the dispersion patterns of the creamer were observed at 2, 4, and 6 volts. When added directly, at 2 and 6 volts, the coffee creamer displayed a pattern of swirling around the vertical axis with some dispersion radially towards the bottom of the beaker. At 4 volts bands were formed, which was likely the result of experimenter error. After the vegetable oil was added, the coffee creamer again displayed as swirls after crossing the oil but was not as distinct as when applied directly.
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Date Issued
2015
PURL
http://purl.flvc.org/fau/fd/FA00005200
Subject Headings
College students --Research --United States.
Format
Document (PDF)
Design and Deployment Analysis of Morphing Ocean Structure
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)
Development of a morphing autonomous underwater vehicle for path and station keeping in complex current environments
Title
Development of a morphing autonomous underwater vehicle for path and station keeping in complex current environments.
Creator
Meneses, Andrea M., Su, Tsung-Chow, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
This thesis explores the feasibility of using morphing rudders in autonomous underwater vehicles (AUVs) to improve their performance in complex current environments. The modeling vehicle in this work corresponds to the Florida Atlantic University's Ocean EXplorer (OEX) AUV. The AUV nonlinear dynamic model is limited to the horizontal plane and includes the effect of ocean current. The main contribution of this thesis is the use of active rudders to successfully achieve path keeping and...
Show moreThis thesis explores the feasibility of using morphing rudders in autonomous underwater vehicles (AUVs) to improve their performance in complex current environments. The modeling vehicle in this work corresponds to the Florida Atlantic University's Ocean EXplorer (OEX) AUV. The AUV nonlinear dynamic model is limited to the horizontal plane and includes the effect of ocean current. The main contribution of this thesis is the use of active rudders to successfully achieve path keeping and station keeping of an AUV under the influence of unsteady current force. A constant ocean current superimposed with a sinusoidal component is considered. The vehicle's response is analyzed for a range of current frequencies.
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Date Issued
2014
PURL
http://purl.flvc.org/fau/fd/FA00004137, http://purl.flvc.org/fau/fd/FA00004137
Subject Headings
Autonomous robots -- Design and construction, Fracture mechanics, Manipulation (Mechanism) -- Control, Remote submersibles -- Design and construction, Vehicles, Remotely piloted -- Design and construction
Format
Document (PDF)
Dynamics and Control of Autonomous Underwater Vehicles with Internal Actuators
Title
Dynamics and Control of Autonomous Underwater Vehicles with Internal Actuators.
Creator
Li, Bo, Su, Tsung-Chow, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
This dissertation concerns the dynamics and control of an autonomous underwater vehicle (AUV) which uses internal actuators to stabilize its horizontalplane motion. The demand for high-performance AUVs are growing in the field of ocean engineering due to increasing activities in ocean exploration and research. New generations of AUVs are expected to operate in harsh and complex ocean environments. We propose a hybrid design of an underwater vehicle which uses internal actuators instead of...
Show moreThis dissertation concerns the dynamics and control of an autonomous underwater vehicle (AUV) which uses internal actuators to stabilize its horizontalplane motion. The demand for high-performance AUVs are growing in the field of ocean engineering due to increasing activities in ocean exploration and research. New generations of AUVs are expected to operate in harsh and complex ocean environments. We propose a hybrid design of an underwater vehicle which uses internal actuators instead of control surfaces to steer. When operating at low speeds or in relatively strong ocean currents, the performances of control surfaces will degrade. Internal actuators work independent of the relative ows, thus improving the maneuvering performance of the vehicle. We develop the mathematical model which describes the motion of an underwater vehicle in ocean currents from first principles. The equations of motion of a body-fluid dynamical system in an ideal fluid are derived using both Newton-Euler and Lagrangian formulations. The viscous effects of a real fluid are considered separately. We use a REMUS 100 AUV as the research model, and conduct CFD simulations to compute the viscous hydrodynamic coe cients with ANSYS Fluent. The simulation results show that the horizontal-plane motion of the vehicle is inherently unstable. The yaw moment exerted by the relative flow is destabilizing. The open-loop stabilities of the horizontal-plane motion of the vehicle in both ideal and real fluid are analyzed. In particular, the effects of a roll torque and a moving mass on the horizontal-plane motion are studied. The results illustrate that both the position and number of equilibrium points of the dynamical system are prone to the magnitude of the roll torque and the lateral position of the moving mass. We propose the design of using an internal moving mass to stabilize the horizontal-plane motion of the REMUS 100 AUV. A linear quadratic regulator (LQR) is designed to take advantage of both the linear momentum and lateral position of the internal moving mass to stabilize the heading angle of the vehicle. Alternatively, we introduce a tunnel thruster to the design, and use backstepping and Lyapunov redesign techniques to derive a nonlinear feedback control law to achieve autopilot. The coupling e ects between the closed-loop horizontal-plane and vertical-plane motions are also analyzed.
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Date Issued
2016
PURL
http://purl.flvc.org/fau/fd/FA00004738, http://purl.flvc.org/fau/fd/FA00004738
Subject Headings
Dynamics., Remote submersibles--Design and construction., Ocean engineering., Fluid dynamics., Nonlinear control theory., Differentiable dynamical systems.
Format
Document (PDF)
Efficient leeway drift prediction
Title
Efficient leeway drift prediction.
Creator
Lee, Yanhua., Florida Atlantic University, Su, Tsung-Chow, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
Search and rescue of crafts in distress on the sea surface require the capability to accurately predict the drift of target craft in a short time. A nonlinear mathematical model (original model) has been developed as a tool for the study of the boat drift. Wind load computation considers the wind gradient and the vessel geometry. The current loads include form and friction drag. From the numerical evaluations, the effects of various environmental and vehical parameters on drift are properly...
Show moreSearch and rescue of crafts in distress on the sea surface require the capability to accurately predict the drift of target craft in a short time. A nonlinear mathematical model (original model) has been developed as a tool for the study of the boat drift. Wind load computation considers the wind gradient and the vessel geometry. The current loads include form and friction drag. From the numerical evaluations, the effects of various environmental and vehical parameters on drift are properly accounted for. Simplification of the original model results in a model which is computationally 60 times faster, so-called version 1, without losing much accuracy. In order to meet the needs of two minute prediction for practical implementation, a further simplified model, version 2, was developed from version 1. It is found that the computing speed can be improved one hundred times, and this will facilitate the practical implementation of FAU model in search planning.
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Date Issued
1989
PURL
http://purl.flvc.org/fcla/dt/14499
Subject Headings
Search and rescue operations--Mathematical models, Ocean currents--Mathematical models, Winds--Speed--Mathematical models
Format
Document (PDF)
Experimental determination of motion-induced force coefficients of long-span bridge models in a water channel
Title
Experimental determination of motion-induced force coefficients of long-span bridge models in a water channel.
Creator
Wei, Li., Florida Atlantic University, Su, Tsung-Chow, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
Wind loads on a bridge may be classified into two types: the buffeting loads and the self-excited loads. The research reported in this thesis is concerned with experimental determination of the self-excited loads in the frequency domain, in particular, their non-dimensional coefficients, called flutter derivatives. The experiments were conducted in a water channel with water substituting for air. Five bridge-section models of different shapes were tested, each of which was driven to move...
Show moreWind loads on a bridge may be classified into two types: the buffeting loads and the self-excited loads. The research reported in this thesis is concerned with experimental determination of the self-excited loads in the frequency domain, in particular, their non-dimensional coefficients, called flutter derivatives. The experiments were conducted in a water channel with water substituting for air. Five bridge-section models of different shapes were tested, each of which was driven to move harmonically by linkages, and the forces on the linkages were measured to determine the fluid loads. A thin-plate model, simulating an airfoil, was also tested and the results were compared with those obtained from the thin airfoil theory. The setup of the experiments and data acquisition, processing and analysis are presented herein.
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Date Issued
1993
PURL
http://purl.flvc.org/fcla/dt/14959
Subject Headings
Bridges, Long-span, Wind-pressure, Bridges--Vibration, Structural dynamics
Format
Document (PDF)
Experimental study of flow over a bundle of cylinders
Title
Experimental study of flow over a bundle of cylinders.
Creator
Khuc, Hiep Hieu., Florida Atlantic University, Su, Tsung-Chow, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
The drag reduction by vortex fusion was investigated. A comparison of flow over a bundle of cylinders in uniform and in disturbed currents was performed in a water channel. The model was subjected to cross flow. A thin cylindrical wire located nearby upstream and leveled at half the height of the test model was used as a source of disturbance. A hydrogen bubble technique was utilized to observe the flow pattern. The accumulation of vortices at stagnating regions in front of a bundle of...
Show moreThe drag reduction by vortex fusion was investigated. A comparison of flow over a bundle of cylinders in uniform and in disturbed currents was performed in a water channel. The model was subjected to cross flow. A thin cylindrical wire located nearby upstream and leveled at half the height of the test model was used as a source of disturbance. A hydrogen bubble technique was utilized to observe the flow pattern. The accumulation of vortices at stagnating regions in front of a bundle of cylinders transformed into a counter-rotated curl at leading edges of each leading cylinder in the bundle. Measurements were carried out by a computerized data acquisition system. Drag coefficient measurements, digital spectral and fourier analyses were also performed. Results have shown that a drag reduction can be obtained by introducing a thin cylindrical wire in front of the stagnation.
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Date Issued
1994
PURL
http://purl.flvc.org/fcla/dt/15026
Subject Headings
Vortex-motion, Fluid dynamics, Cylinders, Fourier transformations, Hydrodynamics
Format
Document (PDF)
Formation of Water Rings Around a Rotating Centroid in Oil
Title
Formation of Water Rings Around a Rotating Centroid in Oil.
Creator
Ferouz, Amir, Gill, Richard, Nasi, Norbert, Pipitone, Anthony, Su, Tsung-Chow, College of Engineering and Computer Science
Abstract/Description
In a tank filled with water at the bottom and oil floating on top, a straight rod reaching into the oil is set to rotate. The rotating rod is brought just above the oil/water boundary and is set to rotate at a speed greater than 200 revolutions per minute. It became evident that the rod’s rotation caused the oil/water interface to curve upward around the center of rotation, reaching up to the bottom of the rotating rod. Visible rings of water formed around the rod, starting at the bottom (at...
Show moreIn a tank filled with water at the bottom and oil floating on top, a straight rod reaching into the oil is set to rotate. The rotating rod is brought just above the oil/water boundary and is set to rotate at a speed greater than 200 revolutions per minute. It became evident that the rod’s rotation caused the oil/water interface to curve upward around the center of rotation, reaching up to the bottom of the rotating rod. Visible rings of water formed around the rod, starting at the bottom (at the oil/water interface) and ascending the rod, one by one. The water rings remained separate and ascended the rod until they eventually dispersed into the oil. Such quantization of water into rings has never been reported on before and represents a novel area of investigation in fluid dynamics. This study aims at obtaining quality photographic evidence to explain this phenomenon.
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Date Issued
2015
PURL
http://purl.flvc.org/fau/fd/FA00005186
Subject Headings
College students --Research --United States.
Format
Document (PDF)
Heating, venting and aerosol particles dynamics in a vacuum clean chamber: An analytical investigation
Title
Heating, venting and aerosol particles dynamics in a vacuum clean chamber: An analytical investigation.
Creator
Li, Jiyue., Florida Atlantic University, Su, Tsung-Chow, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
It is empirically observed and broadly used in the semiconductor manufacturing industry that the clean environment of in-vacuum processing can be enhanced through heating from outside the clean chamber. This paper reports an analytical investigation of this problem and presents the results that confirm the speeding effects of changing the temperature gradient at one end of the clean chamber on venting the aerosol particles from inside the clean chamber. First, a mathematical frame for the...
Show moreIt is empirically observed and broadly used in the semiconductor manufacturing industry that the clean environment of in-vacuum processing can be enhanced through heating from outside the clean chamber. This paper reports an analytical investigation of this problem and presents the results that confirm the speeding effects of changing the temperature gradient at one end of the clean chamber on venting the aerosol particles from inside the clean chamber. First, a mathematical frame for the basic problem is formulated and then various analytical techniques are employed to reduce a set of coupled nonlinear partial differential equations to linear equations, and finally, numerical results are obtained from explicit, analytical formulas.
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Date Issued
1989
PURL
http://purl.flvc.org/fcla/dt/14524
Subject Headings
Clean rooms--Heating and ventilation
Format
Document (PDF)
HYDRODYNAMIC LOADS ON OFFSHORE STRUCTURES DURING SUBSEA BLOWOUTS
Title
HYDRODYNAMIC LOADS ON OFFSHORE STRUCTURES DURING SUBSEA BLOWOUTS.
Creator
RAJIV, PAKANATI V. S., Florida Atlantic University, Su, Tsung-Chow, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
The plume resulting from a subsea well blowout alters the environmental loading on a floating platform which is directly above the well. Horizontal ocean currents deflect the plume and may create a more severe loading on the structure. During the early stages of a blowout the "starting plume" induces forces of a different magnitude on the structure. A preliminary experimental study, investigating the transient loads induced by starting plumes and the effects of currents on blowout plumes, was...
Show moreThe plume resulting from a subsea well blowout alters the environmental loading on a floating platform which is directly above the well. Horizontal ocean currents deflect the plume and may create a more severe loading on the structure. During the early stages of a blowout the "starting plume" induces forces of a different magnitude on the structure. A preliminary experimental study, investigating the transient loads induced by starting plumes and the effects of currents on blowout plumes, was conducted. The results of the experiments showed that the forces involve significant fluctuations which are quite different from the average values. The normal forces induced by starting plumes were slightly greater. Horizontal currents caused an increase in the moment acting on the structure. This is of considerable importance as moments, when coupled with the situation of flooded decks and compartments, may cause the structure to sink.
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Date Issued
1985
PURL
http://purl.flvc.org/fcla/dt/14267
Subject Headings
Offshore structures--Hydrodynamics--Experiments
Format
Document (PDF)
Literature Survey and the Conceptual Design of an Unmanned Arctic Ocean Scientific Vessel
Title
Literature Survey and the Conceptual Design of an Unmanned Arctic Ocean Scientific Vessel.
Creator
Xu, Wenqiang, Su, Tsung-Chow, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
In this paper, the possibility of using a Small Water-plane Area Twin Hull (SWATH) as an unmanned Arctic scientific research vessel is analyzed. Before carrying out the stability analysis of the SWATH ship, this paper briefly outlines the importance of the Arctic survey, which guides the importance of the new research ship for Arctic scientific exploration. In addition to being used as a long-tern monitoring and data collection platform, it is also used as a recovery mothership for autonomous...
Show moreIn this paper, the possibility of using a Small Water-plane Area Twin Hull (SWATH) as an unmanned Arctic scientific research vessel is analyzed. Before carrying out the stability analysis of the SWATH ship, this paper briefly outlines the importance of the Arctic survey, which guides the importance of the new research ship for Arctic scientific exploration. In addition to being used as a long-tern monitoring and data collection platform, it is also used as a recovery mothership for autonomous equipment such as an AUV. After briefly introducing the basic background of a SWATH, it’s advantages and disadvantages are enumerated and analyzed, and a combination of theoretical and practical tests are used to conduct a brief analysis and summary of the reasons for the appearance of trim by head arising from SWATH navigation. Trim by head occurs when a vessel incline such that its plane of flotation is not coincident with its mean waterline plane. In terms of theory, hydrodynamic equations are used to theoretically deduce the SWATH state of navigation and get the corresponding characteristic equation. Finally, a new type USV be designed conceptionally and be created as a model by Solid-work software. Conceptual design combines the advantages of SWATH and remedy deficiency of its longitudinal stability. The theoretical calculation and analysis of the struts of the conceptual model proves that the oblique struts structure can effectively improves the transverse stability of the model, and with the help of the special slender ellipse structure which is installed on the model’s struts, the righting moment of the model is increased when it’s heeling during a large angle. The hydrodynamic analysis of the conceptual model is carried out by Star- CCM software. The simulation results also prove the effectiveness of stabilizer fins to the longitudinal stability of the conceptual design and reflects the data information of the model in terms of resistance and motion state. At last, we have a general understanding of the performance characteristics of the conceptual model by analysis the feedback data, which provides reliable support for future improvement and optimization.
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Date Issued
2018
PURL
http://purl.flvc.org/fau/fd/FA00013155
Subject Headings
Research vessels, Oceanographic research vessels, Automatic control, Design
Format
Document (PDF)
MATHEMATICAL MODELING OF CRAFT DRIFT IN AN OCEAN ENVIRONMENT
Title
MATHEMATICAL MODELING OF CRAFT DRIFT IN AN OCEAN ENVIRONMENT.
Creator
KANG, SIN YOUNG., Florida Atlantic University, Su, Tsung-Chow, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
A mathematical model, which accounts for the essential effects of environmental loads and vehicle characteristics from a fluid dynamics point of view, is developed to forecast the position of a craft drifting on the sea surface. The study is intended to provide a better understanding of the dynamics of drift and thus to provide a reliable model of drift prediction for use in future search and rescue mission. In the mathematical formulation, three degrees of freedom (surge, sway and yaw) of a...
Show moreA mathematical model, which accounts for the essential effects of environmental loads and vehicle characteristics from a fluid dynamics point of view, is developed to forecast the position of a craft drifting on the sea surface. The study is intended to provide a better understanding of the dynamics of drift and thus to provide a reliable model of drift prediction for use in future search and rescue mission. In the mathematical formulation, three degrees of freedom (surge, sway and yaw) of a craft are analyzed, since they play the most significant role in the drift prediction problem. The governing equations of motions are derived from Newton's law of dynamics and the environmental loads considered are the forces and moments exerted by wind, current and waves. The forces are analyzed in terms of drag, lift, and inertial forces. The moments are obtained by summing the contribution from the above forces. For the computation of the wind loads, the wind gradient as well as craft geometry is accounted for. In the current loads, profile, friction and propeller drags are included. The wave forces are computed by the use of wave spectral density. The formulation includes the effects of craft rotation as well as craft translation. A computer algorithm for the mathematical model is implemented to obtain the numerical result in the time domain. The model is verified by comparing its result with field measurements. For this purpose, a field test was carried out. The agreement between the computed and field measured drift path was excellent. The real time prediction capability of the model was ascertained.
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Date Issued
1987
PURL
http://purl.flvc.org/fcla/dt/11894
Subject Headings
Ships--Hydrodynamics--Mathematical models, Ocean waves
Format
Document (PDF)
NOVEL KIRIGAMI-INSPIRED FLEXIBLE ROBOTIC EXTENSION FOR MOBILE PLATFORMS
Title
NOVEL KIRIGAMI-INSPIRED FLEXIBLE ROBOTIC EXTENSION FOR MOBILE PLATFORMS.
Creator
Den Ouden, Casey, Su, Tsung-Chow, Ouyang, Bing, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description
Since 2010, aquaculture practices have produced 70% of global seafood consumption. However, this fast-growing sector of agriculture has yet to see the adoption of advanced technologies to improve farm operations. The Hybrid Aerial Underwater robotiCs System (HAUCS) is an Internet of Things (IoT) framework that aims to bring transformative changes to pond aquaculture. This project focuses on the latest developments in the HAUCS mobile sensing platform and field deployment. A novel rigid...
Show moreSince 2010, aquaculture practices have produced 70% of global seafood consumption. However, this fast-growing sector of agriculture has yet to see the adoption of advanced technologies to improve farm operations. The Hybrid Aerial Underwater robotiCs System (HAUCS) is an Internet of Things (IoT) framework that aims to bring transformative changes to pond aquaculture. This project focuses on the latest developments in the HAUCS mobile sensing platform and field deployment. A novel rigid Kirigami-based robotic extension subsystem was created to expand the functionality of the HAUCS platform. The primary objective of this design was to limit the surface area of an extender arm on the drone during flight operations and minimize the in-flight drag. By utilizing a novel combination of shape memory polymer (SMP) and nitinol to extend and retrieve the sensing arm, the structure was able to conserve energy while operating under varying environmental conditions.
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Date Issued
2023
PURL
http://purl.flvc.org/fau/fd/FA00014324
Subject Headings
Aquaculture, Sensors, Robotics
Format
Document (PDF)
numerical study of bluff body aerodynamics by vortex method
Title
A numerical study of bluff body aerodynamics by vortex method.
Creator
He, Fusen., Florida Atlantic University, Su, Tsung-Chow, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
Vortex methods are grid-free; therefore, their use avoids a number of shortcomings of Eulerian, grid-based numerical methods for solving high Reynolds number flow problems. These include such problems as poor resolution and numerical diffusion. In vortex methods, the continuous vorticity field is discretized into a collection of Lagrangian elements, known as vortex elements. Vortex elements are free to move in the flow field which they create. The velocity field induced by these vortex...
Show moreVortex methods are grid-free; therefore, their use avoids a number of shortcomings of Eulerian, grid-based numerical methods for solving high Reynolds number flow problems. These include such problems as poor resolution and numerical diffusion. In vortex methods, the continuous vorticity field is discretized into a collection of Lagrangian elements, known as vortex elements. Vortex elements are free to move in the flow field which they create. The velocity field induced by these vortex elements is a solution to the Navier-Stokes equation, and in principle the method is suitable for high Reynolds number flows. In this dissertation, viscous vortex element methods are studied. Some modifications are developed. Discrete vortex element methods have been used to solve the Navier-Stokes equations in high Reynolds number flows. Globally satisfactory results have been obtained. However, computed pressure fields are often inaccurate due to the significant errors in the surface vorticity distribution. In addition, different ad hoc assumptions are often used in different proposed algorithms. In the present study, improvements are made to better represent the near-wall vorticity when obtaining numerical solutions for the Navier-Stokes equations. In particular, we split the boundary vortex sheet into two parts at each time step. One part remains a vortex sheet lying on the boundary of the solid body, and the other enters into the flow field as a free vortex element with a uniformly distributed vorticity. A set of kinematic relationships are used to determine the two appropriate portions of the split, and the position of the vortex element to be freed at the time of release. Another improvement is to include the nonlinear acceleration terms in the governing equations near the solid boundary when evaluating the surface pressure distribution. The aerodynamic force coefficients can then be obtained by summing up the pressure forces. By comparing the computed surface vorticities, surface pressures and aerodynamics force coefficients with existing numerical/experimental data in the cases of viscous flow around a circular cylinder, an aerofoil, and a bridge deck section, it is shown that the present approach is more accurate in modelling the flow features and force coefficients without making different ad hoc assumptions for different geometries. The computation is efficient. It can be useful in the study of the unsteady fluid flow phenomenon in practical engineering problems.
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Date Issued
1998
PURL
http://purl.flvc.org/fcla/dt/12574
Subject Headings
Vortex-motion, Fluid mechanics, Viscous flow
Format
Document (PDF)
On the Drainage Vortices of Liquid in a Container with Two Outlets
Title
On the Drainage Vortices of Liquid in a Container with Two Outlets.
Creator
Stankovic, Radivoje, Su, Tsung-Chow, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description
When a liquid drains through a hole in a container, a vortex may form between the surface and the drainage hole. An interesting phenomenon occurs in the presence of two drainage holes. Only one vortex forms, while the other hole will mostly drain as sink flow. In addition, the vortex can switch between one hole and the other with regular periodicity. The primary goal of this study is to measure this periodicity under varying conditions (height of water in the container, diameter of the...
Show moreWhen a liquid drains through a hole in a container, a vortex may form between the surface and the drainage hole. An interesting phenomenon occurs in the presence of two drainage holes. Only one vortex forms, while the other hole will mostly drain as sink flow. In addition, the vortex can switch between one hole and the other with regular periodicity. The primary goal of this study is to measure this periodicity under varying conditions (height of water in the container, diameter of the drainage holes, and distance between drainage holes). Additionally, a study concerning the volume flow rates of vortical vs. sink flow out of the drainage holes was conducted. In the case of two drainage holes, when the height of the water was decreased in the container, the diameter of drainage holes decreased, or the distance between drainage holes was increased, the switching period was shown to decrease.
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Date Issued
2020
PURL
http://purl.flvc.org/fau/fd/FA00013572
Subject Headings
Drainage, Vortex-motion
Format
Document (PDF)
Resulting Hydraulic Jump From Oscillatory Forces Acting on a Pipe
Title
Resulting Hydraulic Jump From Oscillatory Forces Acting on a Pipe.
Creator
Wehage, Tim, Caracci, Christian, Mechmet, Bryan, Garzon, Julian, Su, Tsung-Chow, College of Engineering and Computer Science
Abstract/Description
Within the framework of ongoing research studying the effects of oscillatory forces on pipe flow, an experiment was conducted to investigate the relationship between the nature of said forces and hydraulic jump resulting from the impact of the exiting flow onto an orthogonal surface. To this end, a reservoir supplying constant head and near-hydrostatic conditions was equipped with an exit fitting in its lower section. A section of PVC tubing extended vertically downward from this exit point...
Show moreWithin the framework of ongoing research studying the effects of oscillatory forces on pipe flow, an experiment was conducted to investigate the relationship between the nature of said forces and hydraulic jump resulting from the impact of the exiting flow onto an orthogonal surface. To this end, a reservoir supplying constant head and near-hydrostatic conditions was equipped with an exit fitting in its lower section. A section of PVC tubing extended vertically downward from this exit point and was straddled by a pair of dynamic loudspeakers placed opposite each other and connected to a receiver's inputs so as to play a signal of specified frequency. The resulting turbulent jet flow was then allowed to drop to a horizontal plate of circular shape. The outer lip of the plate triggered a circular hydraulic jump whose location was found to be directly dependent on the frequency of the forces exciting the flow.
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Date Issued
2015
PURL
http://purl.flvc.org/fau/fd/FA00005217
Subject Headings
College students --Research --United States.
Format
Document (PDF)
Separation flow around airfoil with upstream disturbance by discrete vortex method
Title
Separation flow around airfoil with upstream disturbance by discrete vortex method.
Creator
Li, Feng., Florida Atlantic University, Su, Tsung-Chow, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
The discrete vortex method was applied to the calculation of separation flow past NACA 4412 airfoil: Vortex panel was used to represent the body surface and discrete vortices were used to model the wake. Generally the uniform upstream condition is used in the calculation of separation flow. But actually an airfoil could move in wake of other airfoils or disturbed fluid. In this thesis, discrete vortices were used to model the upstream disturbance to investigate the effect of upstream...
Show moreThe discrete vortex method was applied to the calculation of separation flow past NACA 4412 airfoil: Vortex panel was used to represent the body surface and discrete vortices were used to model the wake. Generally the uniform upstream condition is used in the calculation of separation flow. But actually an airfoil could move in wake of other airfoils or disturbed fluid. In this thesis, discrete vortices were used to model the upstream disturbance to investigate the effect of upstream disturbance to the pressure, lift and drag coefficients around the airfoil. Also the animation of separation flow was made on HP workstation using "Starbase" computer graphic package to study the separation process.
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Date Issued
1991
PURL
http://purl.flvc.org/fcla/dt/14739
Subject Headings
Vortex-motion, Fluid dynamics
Format
Document (PDF)

Pages