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Hydrodynamics Of An Anguilliform Swimming Motion Using Morison’S Equation, Naga Sasi Devarakonda 2018 University of New Orleans

Hydrodynamics Of An Anguilliform Swimming Motion Using Morison’S Equation, Naga Sasi Devarakonda

University of New Orleans Theses and Dissertations

In this study, the hydrodynamic performance of anguilliform swimming motion is computed using Morison’s equation. This method was shown to predict the servo motor torques well. The anguilliform swimming motion is sinusoidal with increasing amplitude from head to tail. A “wakeless” swimming motion proposed by Vorus and Taravella (2011) with zero net circulation is considered.

This method is compared to the existing slender body theory and is validated with reference to the experimental results of NEELBOT-1.1 (Potts, 2015). The results for the study indicates that self-propulsion speed of the motion is independent of the oscillating tail amplitude at ...


Purple Urchin Removal, Cullen Goss, Wil Gilbreath, Kevin Marshall 2018 California Polytechnic State University, San Luis Obispo

Purple Urchin Removal, Cullen Goss, Wil Gilbreath, Kevin Marshall

Mechanical Engineering

Soaring purple urchin populations have contributed to a greater than 90% reduction of northern California’s bull kelp forests. Human intervention to reduce the purple urchin population may allow localized kelp patches to grow. The California Department of Fish and Wildlife requested that our team develop a mechanical device to aid in the removal of the urchins. This document provides an update from the scope of work and details the process conducted to reach a scale final design. In this document, we provide background research to show our understanding of urchins and their effect on kelp forests. Then, we analyze ...


Design Of A Robotic Cownose Ray, Mark Marzotto 2018 Union College

Design Of A Robotic Cownose Ray, Mark Marzotto

Honors Theses

Nature often inspires advances in science and technology and a promising example of this is mimicking locomotion of underwater animals. The main ways in which manmade aquatic vehicles propel themselves are water jets and propellers, which are inconsistent with how underwater animals swim. The cownose ray displays very efficient thrust with low frequency strokes by using a combination of oscillations and undulations with its pectoral fins. The goal of this paper is to mechanically replicate the actual fin motion of the cownose ray in order to capture these attractive features. The design will account for both the oscillations by designing ...


Hawai'i Wildlife Fund V. County Of Maui, Lowell J. Chandler 2018 Alexander Blewett III School of Law at the University of Montana

Hawai'i Wildlife Fund V. County Of Maui, Lowell J. Chandler

Public Land & Resources Law Review

In Hawai’i Wildlife Fund v. County of Maui, the Ninth Circuit held that the plain language of the Clean Water Act provides jurisdiction over indirect discharges of pollutants from a point source into groundwater that is shown to be connected to navigable waters. The court found that studies confirmed pollutants entering the Pacific Ocean were fairly traceable to the County of Maui’s sewage disposal wells. In affirming the district court’s ruling, the Ninth Circuit held that Maui County violated the Clean Water Act by discharging pollutants into a navigable water without the required permit. The court also ...


Extending Maneuverability Of Internally Actuated Underwater Gliders, An Attempt To Develop An Open Platform For Research And Education, Saeedeh Ziaeefard 2018 Michigan Technological University

Extending Maneuverability Of Internally Actuated Underwater Gliders, An Attempt To Develop An Open Platform For Research And Education, Saeedeh Ziaeefard

Dissertations, Master's Theses and Master's Reports

Increasing maneuverability of internally actuated Underwater Gliders (UGs) is inevitable due to high demands in underwater surveillance and reconnaissance missions where agility and stealthiness are the keys to success. High maneuverability is needed to provide the opportunity for optimal trajectory planning, planar motion smoothness, and re-planning adapting to the dynamic environments.

This work explores extending the maneuverability of underwater gliders through coupled improvement in mechanical design, efficient use of internal actuation, and motion planning strategy utilizing flight concatenation. The existence of five flight patterns ``advanced flight", inspired by air gliders, enabled solely by utilizing internal actuation are investigated: Circle, Oval ...


Large Eddy Simulation Of Oscillatory Flow Over A Rippled Bed Using An Euler-Lagrange Approach, Daniel S. Hagan 2018 University of Vermont

Large Eddy Simulation Of Oscillatory Flow Over A Rippled Bed Using An Euler-Lagrange Approach, Daniel S. Hagan

Graduate College Dissertations and Theses

A volume-filtered Large-Eddy Simulation (LES) of oscillatory flow over a rippled mobile bed is conducted using an Euler-Lagrange approach. As in unsteady marine flows over sedimentary beds, the experimental data, referenced in this work for validation, shows quasi-steady state ripples in the sand bed under oscillatory flow. This work approximately reproduces this configuration with a sinusoidal pressure gradient driven flow and a sinusoidally rippled bed of particles. The LES equations, which are volume-filtered to account for the effect of the particles, are solved on an Eulerian grid, and the particles are tracked in a Lagrangian framework. In the Discrete Particle ...


Optimal Control Of Wave Energy Converters, Shangyan Zou 2018 MICHIGAN TECHNOLOGICAL UNIVERSITY

Optimal Control Of Wave Energy Converters, Shangyan Zou

Dissertations, Master's Theses and Master's Reports

In this dissertation, we address the optimal control of the Wave Energy Converters. The Wave Energy Converters introduced in this study can be categorized as the single body heaving device, the single body pitching device, the single body three degrees of freedoms device, and the Wave Energy Converters array. Different types of Wave Energy Converters are modeled mathematically, and different optimal controls are developed for them. The objective of the optimal controllers is to maximize the energy extraction with and without the motion and control constraints. The development of the unconstrained control is first introduced which includes the implementation of ...


Streamwise Flow-Induced Oscillations Of Bluff Bodies - The Influence Of Symmetry Breaking, Tyler Gurian 2018 University of Massachusetts Amherst

Streamwise Flow-Induced Oscillations Of Bluff Bodies - The Influence Of Symmetry Breaking, Tyler Gurian

Masters Theses

The influence of symmetry breaking on the flow induced oscillations of bluff bodies in the steamwise direction is studied. First, a series of experiments is conducted on a one-degree-of-freedom circular cylinder allowed to exhibit pure translational motion in the streamwise direction over a range of reduced velocities, 1.4 < U* < 4.4, corresponding to a Reynolds number range of 970 < Re < 3370. Two distinct regions of displacements were observed in reduced velocity ranges of 1.6 < U* < 2.5 and 2.75 < U* < 3.85. Measured force coefficients in the drag and lift direction were examined, along with the wake visualization, through the range of reduced velocities, to infer the resulting wake modes. A new Alternating Symmetric (AS) mode was found. This transition from symmetric to AS shedding occurred near the end of the first region of response. Similar tests were run with a square prism in the parameter space of 2.4 < U* < 5.8 and 757 < Re < 1900 over angles of incidence of 0° ≤ α ≤ 45°. A distinct region of lock-in is observed for α = 0°, 2.5°, 5°, 7.5° over 3.2 < U* < 5.4 for α = 0°, and decreasing with increasing α. The wake structures were found to be roughly symmetric for α = 0°, but transitioned towards asymmetry with ...


Dynamic Modeling And Extreme Tension Analysis Of Mooring System For A Floating Offshore Wind Turbine, Wei Ting Hsu 2017 University of Maine

Dynamic Modeling And Extreme Tension Analysis Of Mooring System For A Floating Offshore Wind Turbine, Wei Ting Hsu

Electronic Theses and Dissertations

For offshore wind industry, exploiting the dynamic behaviors of mooring lines is of increasing importance in floating offshore wind turbine (FOWT) mooring system design. Currently, the design philosophy for structures and moorings is based on principles and practices adopted in offshore oil and gas, including mooring systems that are optimized for applications in deeper waters. However, the design of FOWT mooring systems is facing several challenges, including installation costs, the stability of light-weight minimalistic platforms, and shallow water depths (50-300m). The extreme tension in mooring lines of a light displacement platform in shallow water is dominated by snap loads. Hence ...


Transformation Of Nonlinear Waves In The Presence Of Wind, Current, And Vegetation, Haifei Chen 2017 University of Maine

Transformation Of Nonlinear Waves In The Presence Of Wind, Current, And Vegetation, Haifei Chen

Electronic Theses and Dissertations

Accurate prediction of extreme wave events is crucial for the safe maritime activities and offshore operations. Improved knowledge of wave dissipation mechanisms due to breaking and vegetation leads to accurate wave forecast, protecting life and property along the coast. The scope of the thesis is to examine the wave transformations in the presence of wind, current, and vegetation, using a two-phase flow solver based on the open-source platform OpenFOAM. The Reynolds-Averaged Navier-Stokes (RANS) equations are coupled with a Volume of Fluid (VOF) surface capturing scheme and a turbulence closure model. This RANS-VOF model is adapted to develop a numerical wind-wave-current ...


Vulnerability Assessment Of Critical Bridges In The Hampton Roads Region Of Virginia To Storm Surge Flooding Under Sea Level Rise, Luca Castrucci 2017 Old Dominion University

Vulnerability Assessment Of Critical Bridges In The Hampton Roads Region Of Virginia To Storm Surge Flooding Under Sea Level Rise, Luca Castrucci

Civil & Environmental Engineering Theses & Dissertations

In this thesis, a hydrodynamic model was developed to study the vulnerability of the transportation infrastructure in the Hampton Roads region of Virginia to storm surge flooding under sea level rise. The Hampton Roads region is the second most affected area by relative sea level rise in the United States. The hydrodynamic model was validated for tide prediction, and its performance in storm surge simulation was validated with data from Hurricane Irene (2011). The developed model was then applied to eight flood-prone bridges in the transportation network that connect the cities of Norfolk, Hampton, Virginia Beach, Chesapeake and Portsmouth; the ...


The Application Of Proper Orthogonal Decomposition To Numerically Modeled And Measured Ocean Surface Wave Fields Remotely Sensed By Radar, Andrew Joseph Kammerer 2017 Coastal Carolina University

The Application Of Proper Orthogonal Decomposition To Numerically Modeled And Measured Ocean Surface Wave Fields Remotely Sensed By Radar, Andrew Joseph Kammerer

Electronic Theses and Dissertations

Phase-resolved ocean surface wave elevation maps provide important information for many scientific research areas (e.g., rogue waves, wave-current interactions, and wave evolution/growth) as well as for commercial and defense applications (e.g., naval and shipping operations). To produce these maps, measurements in both time and space are necessary. While conventional wave sensing techniques are limited spatially, marine radar has proven to be a complex yet promising remote sensing tool capable of providing both temporal and spatial wave measurements. The radar return from the sea surface is complex because it contains contributions from many sources only part of which ...


Laboratory Characterization Of Unsteady Boundary Layers, Umair Sarwar, Cary Troy 2017 Purdue University

Laboratory Characterization Of Unsteady Boundary Layers, Umair Sarwar, Cary Troy

The Summer Undergraduate Research Fellowship (SURF) Symposium

The study of waves and their effects on mean flow and turbulence in natural water bodies is an important issue for applications in aquatic biology, coastal engineering, sediment transport and hydrodynamic of the lake. These waves result in the generation of an oscillatory (Stokes) boundary layer near the bottom of the water column. The goal of this study was to conduct various experiments that will be used to characterize the turbulence in unsteady boundary layers and help understand the relation between various flow variables (e.g. wave amplitude, frequency, water depth, turbulent kinetic energy, etc.). Using the research facilities provided ...


Marine Gastrobot Final Design Report, Wesley B. Williams, Eric Kane Dreischerf, Tommy Nicholas Yath 2017 California Polytechnic State University, San Luis Obispo

Marine Gastrobot Final Design Report, Wesley B. Williams, Eric Kane Dreischerf, Tommy Nicholas Yath

Mechanical Engineering

The Marine Gastrobot sponsored by Dr. Christopher Kitts of the Cal Poly Center for Applications in Biotechnology was a research and development effort intended to explore the use of microbial fuel cell technology as a power source for underwater robots. Our team Ocean Locomotion succeeded in developing a first iteration of an underwater robotic platform suitable for microbial fuel cell integration. The primary feature of the design is its sinusoidal fin propulsion intended for benthic exploration with limited risk of entanglement. During the course of development, Ocean Locomotion explored the use of low power actuation methods and determined their limited ...


Micro-Spi Sediment Profile Imaging Micro-Inspector, Andrew P. Corvin, Caleb T. Davies, Matt R. Ferrari 2017 California Polytechnic State University, San Luis Obispo

Micro-Spi Sediment Profile Imaging Micro-Inspector, Andrew P. Corvin, Caleb T. Davies, Matt R. Ferrari

Mechanical Engineering

This project was proposed by Dr. Brian Paavo through a desire to more easily study the benthic sediment layers of the ocean. To do so, he asked us to build a simple and compact machine for use in sediment profile imagery (SPI). Although devices like this already exist, they are all large scale devices that require a ship with a crane to deploy, which is expensive and time consuming. Instead, he desired a “micro” SPI, which is capable of being deployed from a small vessel that can easily navigate shallow waters. Our interpretation of these requirements was as follows: a ...


Motion Dynamics Of Dropped Cylindrical Objects, Gong Xiang 2017 University of New Orleans

Motion Dynamics Of Dropped Cylindrical Objects, Gong Xiang

University of New Orleans Theses and Dissertations

Dropped objects are among the top ten causes of fatalities and serious injuries in the oil and gas industry. Objects may be dropped during lifting or any other offshore operation. Concerns of health, safety, and the environment (HSE) as well as possible damages to structures require the prediction of where and how a dropped object moves underwater. This study of dropped objects is subdivided into three parts. In the first part, the experimental and simulated results published by Aanesland (1987) have been successfully reproduced and validated based on a two-dimensional (2D) theory for a dropped drilling pipe model. A new ...


Low-Frequency Dynamics Of Moored Vessels, Bohdan W. Oppenheim, P. A. Wilson 2017 Loyola Marymount University

Low-Frequency Dynamics Of Moored Vessels, Bohdan W. Oppenheim, P. A. Wilson

Bohdan W. Oppenheim

Three complete theories of the low-frequency dynamics of ships and disks moored with multileg mooring systems in deep water are derived, evaluated, and computerized. One theory is nonlinear; it includes the effects of cubic damping, nonlinear mooring forces and the excitation-yaw motion feedback, and it is handled by simulation. It yields random, regular and transient records, probabilities and statistics, exact and linearized transfer functions, and spectra of responses. The second theory is linear, solved in the frequency domain. The third is a static theory, which is a by-product of the linear one. Mooring lines of arbitrary compositions are considered.


Multi-Modal And Short-Range Transmission Loss In Ice-Covered, Near-Shore Arctic Waters, Miles B. Penhale 2017 Michigan Technological University

Multi-Modal And Short-Range Transmission Loss In Ice-Covered, Near-Shore Arctic Waters, Miles B. Penhale

Dissertations, Master's Theses and Master's Reports

In the past century, extensive research has been done regarding the sound propagation in arctic ice sheets. The majority of this research has focused on low frequency propagation over long distances. One of the most commonly used excitation methods for air-ice-water layers has been explosives. However, environmental regulation has become more stringent, disallowing the use of almost all explosive excitation types. Due to changing climate conditions in these environments, new experimentation is warranted to determine sound propagation characteristics in, through, and under thin ice sheets, in shallow water, over short distances. In April, 2016 several experiments were conducted approximately 2 ...


Wave Motion Induced By Turbulent Shear Flows Over Growing Stokes Waves, Shahrdad Sajjadi, Serena Robertson, Rebecca Harvey, Mary Brown 2016 Embry-Riddle Aeronautical University

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 ...


Numerical Computation Of Transient Response Of 2d Wedge Impact, Naresh Kumar Koyyapu 2016 University of New Orleans

Numerical Computation Of Transient Response Of 2d Wedge Impact, Naresh Kumar Koyyapu

University of New Orleans Theses and Dissertations

The diverse applications of advanced marine craft ascribed to their high speed and technological advancements has led to the use of stronger and lighter metals in such crafts. High speed, in effect also increases slamming loads as higher speed increases frequency of wave encounter while operating in waves. The present study is limited to wedge impact models. Fundamentally, the study is thus about two-dimensional (2D) wedge impact in water. In an attempt to predict the structural response to impact hydrodynamic force, a beam element based finite element (FE) computer program is written and the results of the code are presented ...


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