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Articles 1 - 8 of 8
Full-Text Articles in Ocean Engineering
Reimagining Wind Based Sea Travel With Vertical Axis Wind Turbines, Julian Goins
Reimagining Wind Based Sea Travel With Vertical Axis Wind Turbines, Julian Goins
Discovery Day - Daytona Beach
In the realm of Nautical vehicles, aside from the occasional outliers like rarely used coal steamboats, experimental solar powered ships, or the military grade nuclear vessels, the vast majority of ships run off diesel-powered engines. The unsustainability of such methods will need to be addressed for the security of our planet’s future due to the limited and destructive nature of fossil fuels, much like it already is in many other fields. To that end, this project gains inspiration from the past and looks toward harnessing the power of the wind. In recent times, most sail boats are equipped with some …
Cavitation In Pumps And Propellers: Causes, Effects, Prevention, And Future Trends, Gillian Negron Burgos, Olivia Wilson
Cavitation In Pumps And Propellers: Causes, Effects, Prevention, And Future Trends, Gillian Negron Burgos, Olivia Wilson
Discovery Day - Daytona Beach
In this research, we will explore cavitation in pumps and propellers, including its causes, effects on system performance, prevention methods, and future engineering solutions. Cavitation occurs when the local pressure of a flowing liquid drops below its vapor pressure, forming vapor-filled bubbles that collapse and damage mechanical components. Disciplines such as fluid mechanics, thermodynamics, and materials science contribute to understanding and mitigating cavitation in fluid machinery. When vapor bubbles collapse near metal surfaces, they generate localized shock waves that cause pitting, erosion, vibration, and noise. These effects reduce efficiency, increase maintenance requirements, and shorten the lifespan of rotating machinery used …
Deep Learning Of Semantic Image Labels On Hdr Imagery In A Maritime Environment, Charles Montagnoli
Deep Learning Of Semantic Image Labels On Hdr Imagery In A Maritime Environment, Charles Montagnoli
Doctoral Dissertations and Master's Theses
Situational awareness in the maritime environment can be extremely challenging. The maritime environment is highly dynamic and largely undefined, requiring the perception of many potential hazards in the shared maritime environment. One particular challenge is the effect of direct-sunlight exposure and specular reflection causing degradation of camera reliability. It is for this reason then, in this work, the use of High-Dynamic Range imagery for deep learning of semantic image labels is studied in a littoral environment. This study theorizes that the use HDR imagery may be extremely beneficial for the purpose of situational awareness in maritime environments due to the …
Assessing High Dynamic Range Imagery Performance For Object Detection In Maritime Environments, Erasmo Landaeta
Assessing High Dynamic Range Imagery Performance For Object Detection In Maritime Environments, Erasmo Landaeta
Doctoral Dissertations and Master's Theses
The field of autonomous robotics has benefited from the implementation of convolutional neural networks in vision-based situational awareness. These strategies help identify surface obstacles and nearby vessels. This study proposes the introduction of high dynamic range cameras on autonomous surface vessels because these cameras capture images at different levels of exposure revealing more detail than fixed exposure cameras. To see if this introduction will be beneficial for autonomous vessels this research will create a dataset of labeled high dynamic range images and single exposure images, then train object detection networks with these datasets to compare the performance of these networks. …
Improving Seaglider Efficiency: An Analysis Of Wing Shapes, Hull Morphologies, And Propulsion Methods, Christopher James Hockley
Improving Seaglider Efficiency: An Analysis Of Wing Shapes, Hull Morphologies, And Propulsion Methods, Christopher James Hockley
Doctoral Dissertations and Master's Theses
Autonomous underwater gliders are a family of autonomous underwater vehicles used for long-term observation of oceanic environments. These gliders leverage changes in buoyancy and the resulting vertical motion, to generate forward locomotion via hydrodynamic surfaces. In order to function for extended periods, these systems operate in a low-speed, low-drag regime. This research examines factors impacting the operational efficiencies of gliders, including morphological changes, configuration changes, and propulsion. An interesting question arises when considering the operational efficiencies of conventionally propelled systems at the operating speeds typical of gliders. Can a conventional propulsion system match the efficiency of an underwater glider buoyancy …
An Underwater Vehicle Navigation System Using Acoustic And Inertial Sensors, Khalid M. Alzahrani
An Underwater Vehicle Navigation System Using Acoustic And Inertial Sensors, Khalid M. Alzahrani
Doctoral Dissertations and Master's Theses
Unmanned Underwater Vehicles (UUVs) have become an essential tool for different underwater tasks. Compared with other unmanned systems, the navigation and localization for UUVs are particularly challenging due to the unavailability of Global Positioning System (GPS) signals underwater and the complexity of the unstable environment. Alternative methods such as acoustic positioning systems, Inertial Navigation Systems (INS), and the geophysical navigation approach are used for UUV navigation. Acoustic positioning systems utilize the characteristics of acoustic signals that have a lower absorption rate and a more extended propagation distance than electromagnetic signals underwater. The significant disadvantage of the INS is the “drift,” …
Mission Tasking, Path Planning, And System Integration For An Autonomous Surface Vessel, Timothy Zuercher
Mission Tasking, Path Planning, And System Integration For An Autonomous Surface Vessel, Timothy Zuercher
Doctoral Dissertations and Master's Theses
This thesis presents the design and development of a fully autonomous surface vessel for use as a research platform for the Office of Naval Research and as a competition entry to the International Maritime RobotX Challenge in 2014 and 2016. The author’s contributions to this include the development of safety systems, power distribution systems, communications software, tasking software, and planning algorithms. The results of these developments include a hardware based safety system, a modular power and health monitoring system, an easy to use autoconfiguring inter-process communications stack, a dynamic tasking engine, and a comparison of two solutions to planning with …
Wave Motion Induced By Turbulent Shear Flows Over Growing Stokes Waves, Shahrdad Sajjadi, Serena Robertson, Rebecca Harvey, Mary Brown
Wave Motion Induced By Turbulent Shear Flows Over Growing Stokes Waves, Shahrdad Sajjadi, Serena Robertson, Rebecca Harvey, Mary Brown
Publications
The recent analytical of multi-layer analyses proposed by Sajjadi et al. (J Eng Math 84:73, 2014) (SHD14 therein) is solved numerically for atmospheric turbulent shear flows blowing over growing (or unsteady) Stokes (bimodal) water waves, of low-to-moderate steepness. For unsteady surface waves, the amplitude a(t)∝ekcita(t)∝ekcit, where kcikci is the wave growth factor, k is the wavenumber, and cici is the complex part of the wave phase speed, and thus, the waves begin to grow as more energy is transferred to them by the wind. This will then display the critical height to a point, where the thickness of the inner …