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 Title
 ANALYSIS OF LIQUID IMPACT ON MOVING CONTAINERS.
 Creator
 KANG, SIN YOUNG., Florida Atlantic University, Su, TsungChow, 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 NavierStokes 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 donoracceptor 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 NavierStokes 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 donoracceptor 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.
Show less  Date Issued
 1984
 PURL
 http://purl.flvc.org/fcla/dt/14205
 Subject Headings
 Sloshing (Hydrodynamics)
 Format
 Document (PDF)
 Title
 Hydrodynamic Interactions of Pitching Hydrofoils in Close Formation.
 Creator
 Boltri, Michael A., Curet, Oscar M., Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
 Abstract/Description

Hydrodynamics interaction is a factor in the performance of fish schooling or underwater vessels in close formation. In this work, we visualized the wake structure of pitching hydrofoils using an inclined soap film. We considered one, two, three and ninefoil configurations with different spacing and actuation parameters: amplitude (A), frequency (f), phase difference (), and flow speed (U). The wake structures were recorded with a highspeed camera and analyzed to measure the vortex...
Show moreHydrodynamics interaction is a factor in the performance of fish schooling or underwater vessels in close formation. In this work, we visualized the wake structure of pitching hydrofoils using an inclined soap film. We considered one, two, three and ninefoil configurations with different spacing and actuation parameters: amplitude (A), frequency (f), phase difference (), and flow speed (U). The wake structures were recorded with a highspeed camera and analyzed to measure the vortex angle created. The wake structure of two and threefoil configurations were compared with the Strouhal number, St = fA/U, of a single foil. For the ninefoil configuration, the wake velocity and the standard deviation of the velocity were used to interpret the hydrodynamic interaction. It was found that both spacing and phase difference between foils are relevant in the hydrodynamic interaction. Qualitative observations are also made, and vortex street behavior characteristics are identified.
Show less  Date Issued
 2020
 PURL
 http://purl.flvc.org/fau/fd/FA00013627
 Subject Headings
 Hydrodynamics, Hydrofoils
 Format
 Document (PDF)
 Title
 AN EXPERIMENTAL STUDY OF BIOFOULING ON A FLAT PLATE SUSPENDED IN A UNIFORM FLOW.
 Creator
 WOOD, MARK ALAN., Florida Atlantic University, Tennant, Jeffrey S., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

An investigation was conducted to determine the relationship between hydrodynamic boundary layer parameters and biofouling growth rates. A summary of previous investigations of hydrodynamic effects on biofouling is presented. Wall shear stress is shown to be an important parameter and is described in detail. A submersible water tunnel was designed to allow investigation of a flat plate subject to a uniform flow of seawater. Parallel flow past a flat plate with a laminar boundary layer was...
Show moreAn investigation was conducted to determine the relationship between hydrodynamic boundary layer parameters and biofouling growth rates. A summary of previous investigations of hydrodynamic effects on biofouling is presented. Wall shear stress is shown to be an important parameter and is described in detail. A submersible water tunnel was designed to allow investigation of a flat plate subject to a uniform flow of seawater. Parallel flow past a flat plate with a laminar boundary layer was used to ensure that experimental conditions existed in which a known wall shear stress distribution was establised. Tests were conducted off Virginia Key in Miami, Florida. The results of the experiments clearly indicate the existance of a threshold value of shear stress which inhibits the attachment of the macrofouler under study, the acorn barnacle (Balanus spp.). Reported growth rates from other investigations are presented to substantiate results. Recommendations are made for additional hydrodynamic investigations in dealing with biofouling.
Show less  Date Issued
 1977
 PURL
 http://purl.flvc.org/fcla/dt/13849
 Subject Headings
 Fouling, Hydrodynamics
 Format
 Document (PDF)
 Title
 BEHAVIOR OF A SWIRLING BUOYANT TURBULENT JET IN A CROSS FLOW.
 Creator
 VISWANATHAN, SURESH., Florida Atlantic University, Su, TsungChow, 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.
Show less  Date Issued
 1986
 PURL
 http://purl.flvc.org/fcla/dt/14317
 Subject Headings
 Jets, Hydrodynamics
 Format
 Document (PDF)
 Title
 Flow visualization of the ventilated cavities generated by a surface piercing propeller.
 Creator
 Altamirano, Luis., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

In the present study, 3 wake parameters are semiautomatically measured in 63 compositelabeled images of a surface piercing propeller tested at yaw angles 030 degrees, pitch angles 015 degrees, propeller immersion ratios of 0.33 and 0.50 and scaled advance ratios 0.6561.927. A fourth wake parameter is measured in four composite labeled images of yaw angles 030 degrees, pitch angle 0 degrees, immersion ratios of 0.33 and 0.50 and scaled advance ratios 1.3631.927. Measurements are plotted...
Show moreIn the present study, 3 wake parameters are semiautomatically measured in 63 compositelabeled images of a surface piercing propeller tested at yaw angles 030 degrees, pitch angles 015 degrees, propeller immersion ratios of 0.33 and 0.50 and scaled advance ratios 0.6561.927. A fourth wake parameter is measured in four composite labeled images of yaw angles 030 degrees, pitch angle 0 degrees, immersion ratios of 0.33 and 0.50 and scaled advance ratios 1.3631.927. Measurements are plotted against propeller's angular position. Major findings include the behavior of wake parameters as the values of scaled advance ratio, yaw angle, pitch angle, and immersion ratio vary.
Show less  Date Issued
 2010
 PURL
 http://purl.flvc.org/FAU/1927299
 Subject Headings
 Ships, Hydrodynamics, Ship propulsion
 Format
 Document (PDF)
 Title
 EXCITATION OF EDGE WAVES BY WAVES OBLIQUELY INCIDENT UPON A BEACH.
 Creator
 CHANG, YUHHUEI., Florida Atlantic University, Lin, Newman K.
 Abstract/Description

Edge waves are the longshore periodic wave motions that are trapped at the edge of water bodies and play an important role in coastal hydrodynamics. This study presents the experimental investigation of the excitation of synchronous edge waves by waves normally and obliquely incident on a uniformly sloping beach. The experimental results show that the edge wave amplitude is linearly proportional to that of the reflected waves. For a perfectly reflecting beach, the conclusion is consistent...
Show moreEdge waves are the longshore periodic wave motions that are trapped at the edge of water bodies and play an important role in coastal hydrodynamics. This study presents the experimental investigation of the excitation of synchronous edge waves by waves normally and obliquely incident on a uniformly sloping beach. The experimental results show that the edge wave amplitude is linearly proportional to that of the reflected waves. For a perfectly reflecting beach, the conclusion is consistent with the Rockliff model. The experimental results also indicate that the ratio of the edge wave amplitude to reflected amplitude is linearly proportional to the approach angle.
Show less  Date Issued
 1987
 PURL
 http://purl.flvc.org/fcla/dt/14380
 Subject Headings
 Ocean waves, Hydrodynamics
 Format
 Document (PDF)
 Title
 Feasibility study of high performance submarine craft.
 Creator
 Yao, Jianguo., Florida Atlantic University, Wong, TinLup, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

The goal in developing submarines for military purposes is to make them high performance and highly maneuverable. Thus, the size of the submarine should be compatible with these goals. The size of the submarine is heavily dependent on the efficiency of the power plant. A nuclear power plant has many more advantages than a conventional dieselelectric powerplant. However, today's technology is not advanced enough to make a nuclear power plant small and light enough for a small submarine craft....
Show moreThe goal in developing submarines for military purposes is to make them high performance and highly maneuverable. Thus, the size of the submarine should be compatible with these goals. The size of the submarine is heavily dependent on the efficiency of the power plant. A nuclear power plant has many more advantages than a conventional dieselelectric powerplant. However, today's technology is not advanced enough to make a nuclear power plant small and light enough for a small submarine craft. Therefore, this thesis focuses on the fuel cell power plant study, configuration design, and dynamic behavior simulation. A mathematical model for the dynamic motion simulation is developed. The dynamic behavior simulations are carried out and analyzed.
Show less  Date Issued
 1988
 PURL
 http://purl.flvc.org/fcla/dt/14450
 Subject Headings
 Submarine boatsHydrodynamics
 Format
 Document (PDF)
 Title
 ANALYSIS OF HYDRODYNAMIC INTERACTIONS BETWEEN SHIPS IN CONFINED WATERS.
 Creator
 Ananthakrishnan, Palaniswamy, Florida Atlantic University, Lin, Newman K.
 Abstract/Description

The hydrodynamic interactions between ships in confined waters, restricted in width and depth, is analysed using a numerical surface singularity method called the Panel method. Based on potential flow and rigid free surface assumptions, a source distribution is utilized over the boundary surfaces to model the flow. The strength of the source distribution is obtained on satisfying the normal kinematic boundary conditions, i.e. as a solution of an integral equation. Discretization of the...
Show moreThe hydrodynamic interactions between ships in confined waters, restricted in width and depth, is analysed using a numerical surface singularity method called the Panel method. Based on potential flow and rigid free surface assumptions, a source distribution is utilized over the boundary surfaces to model the flow. The strength of the source distribution is obtained on satisfying the normal kinematic boundary conditions, i.e. as a solution of an integral equation. Discretization of the boundary surfaces yields a system of linear algebraic equations corresponding to the boundary integral equation, which then is solved numerically. From the singularity distribution, the velocity components, pressure coefficients and finally the interaction loads are calculated.
Show less  Date Issued
 1985
 PURL
 http://purl.flvc.org/fcla/dt/14272
 Subject Headings
 ShipsHydrodynamics
 Format
 Document (PDF)
 Title
 Open water testing of a surface piercing propeller with varying submergence, yaw angle and inclination angle.
 Creator
 Lorio, Justin M., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

The use of surface piercing propellers (SPPs) shows promise for high speed operation by virtually eliminating appendage drag, which can be as much as 30 percent of the total drag on a vehicle at high speeds. The scarcity of available systematic test data has made reliable performance prediction difficult. The primary objective of this research is to obtain experimental performance prediction data that can be used in SPP design. In a series of open water tests in a nonpressurized towing tank...
Show moreThe use of surface piercing propellers (SPPs) shows promise for high speed operation by virtually eliminating appendage drag, which can be as much as 30 percent of the total drag on a vehicle at high speeds. The scarcity of available systematic test data has made reliable performance prediction difficult. The primary objective of this research is to obtain experimental performance prediction data that can be used in SPP design. In a series of open water tests in a nonpressurized towing tank facility, force transducer measurements were taken at tip immersion ratios from 0.5 to .33, yaw angles from 0° to 30° and inclination angles from 0° to 15° over a range of advance ratios from 0.8 to 1.8. Force transducer measurements were taken for thrust, torque, side forces and moments. These results will help develop a baseline for the verification of SPP performance prediction.
Show less  Date Issued
 2010
 PURL
 http://purl.flvc.org/FAU/1930498
 Subject Headings
 Ships, Hydrodynamics, Ship propulsion, Propellers
 Format
 Document (PDF)
 Title
 HYDRODYNAMIC LOADS ON OFFSHORE STRUCTURES DURING SUBSEA BLOWOUTS.
 Creator
 RAJIV, PAKANATI V. S., Florida Atlantic University, Su, TsungChow, 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.
Show less  Date Issued
 1985
 PURL
 http://purl.flvc.org/fcla/dt/14267
 Subject Headings
 Offshore structuresHydrodynamicsExperiments
 Format
 Document (PDF)
 Title
 Computation of hydrodynamic coefficients and determination of dynamic stability characteristics of an underwater vehicle including free surface effects.
 Creator
 Saout, Olivier., Florida Atlantic University, Ananthakrishnan, Palaniswamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

The inviscid hydrodynamic coefficients of an underwater vehicle (Ocean EXplorer), including the nonlinear effects of the wave surface, are computed using a boundaryintegral method. A mixed EulerianLagrangian formulation (LonguetHiggins and Cokelet, 1976) is used for the treatment of nonlinear freesurface conditions. The algorithm is validated using the workenergy theorem (Yeung, 1982) and experimental data. Results, in the form of freesurface elevations and hydrodynamic coefficients,...
Show moreThe inviscid hydrodynamic coefficients of an underwater vehicle (Ocean EXplorer), including the nonlinear effects of the wave surface, are computed using a boundaryintegral method. A mixed EulerianLagrangian formulation (LonguetHiggins and Cokelet, 1976) is used for the treatment of nonlinear freesurface conditions. The algorithm is validated using the workenergy theorem (Yeung, 1982) and experimental data. Results, in the form of freesurface elevations and hydrodynamic coefficients, are obtained for a range of body geometries and maneuvers. The openloop dynamics of underwater vehicles are then investigated by solving the 3DOF rigidbody equations of motion (OXY plane). The advantages and possible usage of the developed methodology for the design and control of underwater vehicles, as well as topics for further research, are addressed in the conclusion chapter of the thesis.
Show less  Date Issued
 2003
 PURL
 http://purl.flvc.org/fcla/dt/12981
 Subject Headings
 Hydrodynamics, Oceanographic submersibles, Water waves
 Format
 Document (PDF)
 Title
 Solids hydrodynamics and heat transfer to inline and staggered tube banks in large particle fluidized beds.
 Creator
 Darda, Monish M., Florida Atlantic University, Moslemian, Davood
 Abstract/Description

A Computer Automated Radioactive Particle Tracking (CARPT) facility was designed and implemented for the investigation of hydrodynamics in two phase flows. This facility was complemented by a versatile fluidized bed facility capable of handling high air flow rates. Solids mean dynamic behavior and heat transfer to internals in a 29.21 cm diameter fluidized bed were investigated for different operating conditions. Different flow parameters like the solids ensembleaveraged velocity, stagnancy...
Show moreA Computer Automated Radioactive Particle Tracking (CARPT) facility was designed and implemented for the investigation of hydrodynamics in two phase flows. This facility was complemented by a versatile fluidized bed facility capable of handling high air flow rates. Solids mean dynamic behavior and heat transfer to internals in a 29.21 cm diameter fluidized bed were investigated for different operating conditions. Different flow parameters like the solids ensembleaveraged velocity, stagnancy and the phase density in the presence of horizontal tubes were determined using the CARPT facility. Local circumferential variations of heat transfer coefficients at the surface of horizontal tubes were measured at different locations in a large particle fluidized bed using a miniature heat transfer probe assembly. The influence of solids hydrodynamics on the heat transfer coefficient in gasfluidized beds was investigated. The data obtained in the present study was compared to current heat transfer models for large particle gasfluidized beds.
Show less  Date Issued
 1990
 PURL
 http://purl.flvc.org/fcla/dt/14576
 Subject Headings
 HeatTransmission, Hydrodynamics, Fluidization
 Format
 Document (PDF)
 Title
 Salinity simulation in Florida Bay with the Regional Oceanic Modeling System (ROMS).
 Creator
 Siddke, Abu Bakar, Chérubin, Laurent, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

Understanding and resolving the water quality problems that Florida Bay has endured requires an understanding of its salinity drivers. Because salinity is the prime factor that drives estuarine ecosystem, Florida Bay’s ecosystem health depends on the correct salinity balance of the Bay. In this thesis, the Regional Oceanic Modeling System  a hydrodynamic prognostic model was implemented on Florida Bay and it was tailored for shallow waters. Results show that the model captures most of the...
Show moreUnderstanding and resolving the water quality problems that Florida Bay has endured requires an understanding of its salinity drivers. Because salinity is the prime factor that drives estuarine ecosystem, Florida Bay’s ecosystem health depends on the correct salinity balance of the Bay. In this thesis, the Regional Oceanic Modeling System  a hydrodynamic prognostic model was implemented on Florida Bay and it was tailored for shallow waters. Results show that the model captures most of the salinity spatial and temporal variability of Florida Bay. Furthermore, it establishes the role of the major drivers like evaporation, precipitation, and runoff on Florida Bay’s salinity. The model resolves region specific salinity drivers in all four areas of Florida Bay characterized by their own salinity regimes. The model was also able to reveal the impact of surface runoff on salinity in the later part of the year when evaporation increases. A new technique was developed to estimate the discharge and salinity of unmonitored small creeks north of Florida Bay. Those data were estimated from the relationship between net freshwater flux, runoff, and salinity. Model results revealed the importance of accounting for these small creeks to accurately simulate Florida Bay’s salinity.
Show less  Date Issued
 2018
 PURL
 http://purl.flvc.org/fau/fd/FA00005996
 Subject Headings
 Florida Bay (Fla.), Salinity, HydrodynamicsMathematical models, HydrodynamicsComputer simulation, EstuariesHydrodynamics
 Format
 Document (PDF)
 Title
 A physical description of longperiodnet displacement variation within the southern Indian River Lagoon, Florida.
 Creator
 Sternberger, M. S., Harbor Branch Oceanographic Institute
 Date Issued
 1983
 PURL
 http://purl.flvc.org/fau/fd/FA00007479
 Subject Headings
 Indian River (Fla. : Lagoon)., EstuariesHydrodynamics.
 Format
 Document (PDF)
 Title
 An investigation of nearbottom flow patterns along and across Hawk Channel, Florida Keys.
 Creator
 Pitts, Patrick A., Harbor Branch Oceanographic Institute
 Date Issued
 1994
 PURL
 http://purl.flvc.org/FCLA/DT/3172796
 Subject Headings
 Ocean currents, Tides, Tidal currents, Hydrodynamics, Oscillations
 Format
 Document (PDF)
 Title
 An introduction to the tides of Florida's Indian River lagoon. Part II: currents.
 Creator
 Smith, Ned P.
 Date Issued
 1990
 PURL
 http://purl.flvc.org/FCLA/DT/3183162
 Subject Headings
 Tides, TidesMeasurement, Estuaries Hydrodynamics
 Format
 Document (PDF)
 Title
 Hydrodynamic analysis of an underwater body including freesurface effects.
 Creator
 Puaut, Christophe., Florida Atlantic University, Ananthakrishnan, Palaniswamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

Boundary integral algorithms are developed to analyze threedimensional inviscid fluidbody interactions, including the nonlinear freesurface effects. Hydrodynamic coefficients are computed for various body geometries, some corresponding to that of small underwater vehicles, in deep waters and near the free surface. The fully nonlinear unsteady waveradiation problem corresponding to forced submergedbody oscillations and forward translation are solved using the mixed EulerianLagrangian...
Show moreBoundary integral algorithms are developed to analyze threedimensional inviscid fluidbody interactions, including the nonlinear freesurface effects. Hydrodynamic coefficients are computed for various body geometries, some corresponding to that of small underwater vehicles, in deep waters and near the free surface. The fully nonlinear unsteady waveradiation problem corresponding to forced submergedbody oscillations and forward translation are solved using the mixed EulerianLagrangian formulation (LonguetHiggins and Cokelet, 1976). By implementing the leadingorder freesurface conditions on the calm surface, linear timedomain solutions are also obtained. The nonlinear and linear results are compared to quantify the nonlinear freesurface effects. Linear frequencydomain analysis of the wavebody interactions is also carried out using a boundaryintegral method based on the simplesource distribution (Yeung, 1974). The linear timedomain and the latter frequencydomain results are also compared for a validation of the algorithms.
Show less  Date Issued
 2001
 PURL
 http://purl.flvc.org/fcla/dt/12845
 Subject Headings
 Boundary element methods, Oceanographic submersibles, Hydrodynamics
 Format
 Document (PDF)
 Title
 PROBE MEASUREMENTS IN A LISITANO COIL CREATED, MAGNETICALLY CONFINED HYDROGEN PLASMA.
 Creator
 SAEKS, JEFFREY IAN., Florida Atlantic University
 Abstract/Description

Hydrogen plasmas were produced in an axially symmetric magnetic field which was nearly uniform in the Lisitano coil region. The field could be converted from a shallow mirror to a deep mirror (R = 44), to a cusp geometry by varying the current ratio in two sets of magnet coils. Unguarded Langmuir probes and a periodic potential probe proved unsatisfactory due to sheath growth. A gridded Langmuir probe measured ion temperature of 26 eV and electron temperature of 9 eV, with ion density 7 to...
Show moreHydrogen plasmas were produced in an axially symmetric magnetic field which was nearly uniform in the Lisitano coil region. The field could be converted from a shallow mirror to a deep mirror (R = 44), to a cusp geometry by varying the current ratio in two sets of magnet coils. Unguarded Langmuir probes and a periodic potential probe proved unsatisfactory due to sheath growth. A gridded Langmuir probe measured ion temperature of 26 eV and electron temperature of 9 eV, with ion density 7 to 10x10^8 cm^3. The magnetic boundary value problem was solved analytically and comparison with previous experiments at Florida Atlantic University showed the electron temperature to depend on the magnetic field gradient in the Lisitano coil. It was also seen that high voltage (250 V) on the periodic probe was not ionizing neutrals.
Show less  Date Issued
 1978
 PURL
 http://purl.flvc.org/fcla/dt/13905
 Subject Headings
 Hydrodynamics, Plasma probes, MagnetismExperiments
 Format
 Document (PDF)
 Title
 MATHEMATICAL MODELING OF CRAFT DRIFT IN AN OCEAN ENVIRONMENT.
 Creator
 KANG, SIN YOUNG., Florida Atlantic University, Su, TsungChow, 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.
Show less  Date Issued
 1987
 PURL
 http://purl.flvc.org/fcla/dt/11894
 Subject Headings
 ShipsHydrodynamicsMathematical models, Ocean waves
 Format
 Document (PDF)
 Title
 Sound generated due to vortical flow past a forward facing step.
 Creator
 Gundlapalli, Ravishankar., Florida Atlantic University, Dhanak, Manhar R.
 Abstract/Description

The sound field associated with the motion of 2dimensional finite core vortex past a forward facing step is obtained. A numerical scheme using Contour Dynamics technique and incompressible, inviscid equations of motion is developed to determine the evolution of the structure of the vortex, its path over the step and the radiated sound. An appropriate lowfrequency Green's function is derived and the expression for the far field acoustic pressure as formulated by Mohring is used. The vortex...
Show moreThe sound field associated with the motion of 2dimensional finite core vortex past a forward facing step is obtained. A numerical scheme using Contour Dynamics technique and incompressible, inviscid equations of motion is developed to determine the evolution of the structure of the vortex, its path over the step and the radiated sound. An appropriate lowfrequency Green's function is derived and the expression for the far field acoustic pressure as formulated by Mohring is used. The vortex structure evolves in the nonuniform flow in the vicinity of the step and under certain conditions is found to undergo significant deformation of its core structure. The far field acoustic pressure is found to be a strong function of vortex motion in the vicinity of the step. Results for the vortex trajectory and the associated acoustic pressure are presented for a variety of flow parameters.
Show less  Date Issued
 1992
 PURL
 http://purl.flvc.org/fau/fd/FADT14825
 Subject Headings
 Underwater acoustics, Vortexmotion, Eddies, Hydrodynamics
 Format
 Document (PDF)