Current Search: Hydrodynamics--Mathematical models. (x)
View All Items
(1 - 7 of 7)
- 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.
Show less - Date Issued
- 1987
- PURL
- http://purl.flvc.org/fcla/dt/11894
- Subject Headings
- Ships--Hydrodynamics--Mathematical models, Ocean waves
- Format
- Document (PDF)
- Title
- Tidal and long-term volume transport through Jewfish Creek, Florida Keys.
- Creator
- Pitts, Patrick A., Harbor Branch Oceanographic Institute
- Date Issued
- 1998
- PURL
- http://purl.flvc.org/FCLA/DT/3171648
- Subject Headings
- Tides --Florida --Biscayne Bay, Hydrodynamics --Mathematical models, Stream measurements, Water --Analysis, Estuarine ecology
- Format
- Document (PDF)
- Title
- Volume transport variability through the Florida Keys tidal channels.
- Creator
- Lee, Thomas N., Smith, Ned P.
- Date Issued
- 2002
- PURL
- http://purl.flvc.org/FCLA/DT/2848307
- Subject Headings
- Hydrodynamics --Mathematical models, Florida Keys (Fla.), Tidal currents, Coastal zone management, Sea level
- Format
- Document (PDF)
- Title
- Tidal, low-frequency and long-term mean transport through two channels in the Florida Keys.
- Creator
- Smith, Ned P.
- Date Issued
- 2002
- PURL
- http://purl.flvc.org/FCLA/DT/2848305
- Subject Headings
- River channels, Florida Keys (Fla.), Hydrodynamics --Mathematical models, Ocean-atmosphere interaction, Hydraulic measurements
- Format
- Document (PDF)
- Title
- Transport processes linking shelf and back reef ecosystems in the Exuma Cays, Bahamas.
- Creator
- Smith, Ned P.
- Date Issued
- 2004
- PURL
- http://purl.flvc.org/FCLA/DT/3171655
- Subject Headings
- Coral reef ecology --Research, Tides, Ocean currents, Winds, Hydrodynamics --Mathematical models
- 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, Hydrodynamics--Mathematical models, Hydrodynamics--Computer simulation, Estuaries--Hydrodynamics
- 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.
Show less - 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)
