Ocean Engineering Commons^™

Extending Low-Frequency Traveling-Wave Propagation In A Water-Filled Cylindrical Waveguide Using Active Impedance Control, William Slater

Open Access Dissertations

This dissertation investigates extending the frequency range over which a one-dimensional, plane traveling wave can be generated in a water-filled, steel-walled waveguide under ocean temperature and hydrostatic pressure conditions. The wave guide considered is a thick-walled, steel cylinder filled with a water/glycol mixture with a transducer at each end and a hydrophone array along the length. One transducer excites a plane wave while the other cancels reflections, resulting in a traveling wave in the waveguide. The current (open-loop) measurement system is advertised to generate traveling waves for low frequencies where only 3.4% of a wavelength can be measured (kL …

Development Of An Active Heave Compensation System On A Cost Effective Microcontroller For A Fiber Optic Tether Management System, Frances Truong

Open Access Master's Theses

Fiber optic tether systems are used for real-time data transmission to remotely operated vehicles (ROV) due to their ease of deployment and light weight, but are prone to damage from tension loads. An active heave compensation system applied to a fiber optic tether system can address these challenges by actively managing the tether payout to reduce peak loads. Tether management systems with active heave compensation have been in use for larger systems such as work class vehicles and offshore oil rigs, but few are developed for small maritime systems. This work focuses on the development and incorporation of an active …

Vortex-Vortex Interaction Cavitation Inception Using Statistical And Multi-Phase Models, Nicholas Berthiaume

Open Access Master's Theses

This document is not being released in full, as it contains Controlled Unclassified Information (CUI) subject to safeguarding and dissemination controls under the policies of the National Institute for Undersea Vehicle Technology (NIUVT). Only those portions authorized for release are included herein.

Development And Deployment Of In Situ Fiber Optic Distributed Temperature Sensing Systems And Data Processing Workflows For Oceanographic Observatories In Coastal And Deep-Sea Environments, Johann Sebastian Becker

Open Access Dissertations

Over the last two decades, fiber optic distributed temperature sensing (DTS) has emerged as a transformative technology capable of providing unprecedented spatiotemporal resolution observations of temperature in a broad range of environmental sensing, industrial, and civil engineering monitoring applications. DTS uses a single interrogator unit to measure temperature continuously along an optical fiber, effectively turning the fiber into the equivalent of an array of temperature probes that can be interrogated synoptically. Modern commercially-available DTS systems are capable of continuous sensing with sampling frequencies up 5 sec, spatial resolution of 0.25 m, and temperature precision up to 0.01 °C) observations, on …

Finite Element Modeling Of Offshore Wind Monopile Impact Pile Driving In Comsol Multiphysics, Brendan J. Giordano

Open Access Master's Theses

The primary foundation type for offshore wind farms are large-diameter monopiles, which are installed with an impact hammer that produces a high-intensity, broadband impulsive signal that radiates acoustic energy in the water column and seafloor. This signal generates multiple waves such as compressional, shear and Scholte (or interface) waves. Scholte waves travel on the water-sediment interface and contain high-intensity, low-frequency energy that benthic species of fish and invertebrates could possibly detect. COMSOL Multiphysics, which is a finite element modeling software, was used to develop two transient models of impact pile driving to measure Scholte wave particle motion (displacement, velocity, acceleration) …

Optical-Link-Aware Online Waypoint Planner For Asv-Auv Systems, Ansel R. Austin

Open Access Master's Theses

The growing demand for ocean mapping and survey missions has increased interest in reliable AUV-ASV platforms. In such systems, reliable communication between the AUV and ASV is critical for monitoring the AUV's status and offloading large data products such as multi-beam sonar point clouds. While the range of acoustic telemetry can span several kilometers, its bandwidth is inadequate for transmitting high-volume data streams (such as images and point clouds). Underwater optical communication modems, in contrast, provide a relatively high bandwidth but are hindered by rapid attenuation in turbid water and a narrow field of view. This thesis introduces an online, …

Develop A Cross-Platform Toolset For In Situ Deep-Sea Coral Propagation, Joe Bevilacqua

Open Access Master's Theses

Mesophotic and deep-sea gorgonian octocorals in the Gulf of Mexico were significantly damaged following the Deepwater Horizon oil spill, prompting a major federal investment in developing restoration techniques for these fragile, slow-growing communities. Asexual, in-situ coral propagation offers a biologically viable path for restoration at depth. However, current ROV systems are not optimized for the delicate, fine-scale interactions required to perform this process reliably. The objective of this research was to design, prototype, and evaluate a ROV-mountable toolset capable of preparing octocoral fragments for potting in epoxy substrate, with the additional goal of integrating the toolset into URI’s Coral Carousel …

Reverse Geometric Dispersion In The Beaufort Sea: Dissecting Sound Propagation At Long Ranges In Ducted Profiles, Jessica Desrochers

Open Access Dissertations

Acoustic propagation in the Arctic is evolving as surface temperatures increase and ice melts, resulting in a changing sound propagation environment. This study investigates the acoustic arrival structure in the Canada Basin and its connection to the underlying sound speed profiles. Two Seagliders were deployed in the summer of 2016 and 2017, diving in a sawtooth pattern collecting conductivity, temperature, and depth (CTD) data as part of the Canada Basin Acoustic Glider Experiment (CABAGE). These data are used to calculate sound speed profiles used to predict and understand acoustic arrival structures.

The warming of the Pacific Summer Water and surface …

Design And Deployment Of A Compact Rov For Deep-Sea Research And Exploration, Joshua F. Wood

Open Access Master's Theses

The scientific community has utilized unmanned underwater vehicles for ocean exploration since the mid-twentieth century, resulting in a well-cultivated and ever-changing discipline of ocean technology. The deep-sea environment, specifically, presents unique and harsh criteria due to the increased pressure found at depth and the vehicle components necessary to overcome it. The size and weight of underwater vehicles typically increase as operational depth increases, resulting in physically large systems with high operational costs to accommodate deep-sea research. This project first characterized the effect of length and diameter on carbon fiber pressure housing’s depth tolerance. It then leveraged this data to reduce …

The Coral Carousel: A Device And Method For In-Situ Propagation Of Deep-Sea Corals, Gregory Bales

Open Access Master's Theses

The research described herein covers the development of a tool station for performing in-situ propagation of corals using a work class ROV. This includes a system for manipulating coral fragments and affixing them to a cement base plug. To validate this tool station, testing was performed both in the lab as well as at depth in the Gulf of Mexico. As restoration of shallow-water corals has grown in popularity, many techniques have been developed for propagation. However, it is difficult or inappropriate to directly apply these techniques to deep-sea corals. While some forms of diving are capable of approaching the …

Dynamic Beamforming And Array Shape Estimation, Nicholas Ryan Costick

Open Access Master's Theses

The accurate estimation of towed sonar array shapes during complex maneuvers is a critical challenge affecting beamforming and target localization performance. When underwater arrays experience sharp turns or rapid movements, sensor positions become difficult to track precisely, negatively impacting the reliability of beamforming methods. This thesis addresses the issue of dynamic array shape uncertainty, motivated by operational challenges faced by the Navy.

A maximum-likelihood estimation (MLE) method is developed to simultaneously estimate the array shape and field directionality (spatial spectrum) during maneuvers. The proposed solution expands upon previous research, specifically the dynamic spatial spectrum estimation techniques described by Rogers and …

Experimental Validation Of Model Predictive Control For Roll Attenuation Of Scale Model Barge In Beam Sea Conditions, Callum Robbins

Open Access Master's Theses

Floating offshore wind turbines (FOWTs) are the next great frontier in the offshore energy world. However, for these machines to be safe, effective, and reliable, they must be stable. In this thesis, an active control strategy is developed that uses future wave information and model predictive control to attenuate wave induced motions of a floating platform, such as a FOWT. The future wave information is provided by a wave reconstruction and prediction (WRP) algorithm which allows for wave events to be calculated faster than real-time. This wave information is provided to a nonlinear model predictive controller (NMPC) that uses a …

Experimental Design Considerations Of Gravity-Capillary Wave - Current Interaction In A Lab, Erin Hub

Open Access Master's Theses

An experiment was designed to create a dataset of wave-current interaction of gravity-capillary waves and currents of similar magnitude to understand how the wave elevation field is modulated by the current. The data product from the experiments will be spatial plots of the wave elevation field of the refracted waves by the current for a range of speeds, headings, and wave periods. The field of view in these spatial plots includes portions of the undisturbed wavefield, a current region of finite width where the waves pass through, and the refracted wavefield on the opposite side of the current.

To verify …

Control Of Flow Instabilities With Acoustic Metamaterials, Jensen E. Mctighe

Open Access Master's Theses

Acoustic metamaterials (AMs) have been proposed for uses in flow control, as they offer a passive control method and can be engineered independently, without needing complex fluid structure interactions simulations. For example, AMs embedded into flat plate surfaces have been demonstrated to delay (or speed up) the onset of laminar-to-turbulent boundary layer transition by attenuating (or strengthening) Tollmein-Schlicting waves through numerical simulation. However, as of present, no experimental research has been conducted to study or demonstrate the behaviors of AMs designed to interact with flow structures. An experiment was performed in which an AM was embedded into a flat plate …

Observability-Aware Path Planning For Autonomous Navigation, Raymond Brink Neistat

Open Access Master's Theses

Terrain-Aided Navigation (TAN) is a popular method of localization for GPS-denied vehicles, particularly in the marine domain. There are many ways to perform TAN in a marine setting, such as Bathymetric SLAM (BSLAM) and Bayesian Filtering with the aid of an a priori map. These techniques have been studied extensively, but show an overall lack of rigorous observability analyses. Without nonlinear observability analyses, TAN practitioners do not have an analytical indicator to know which areas of terrain will provide opportunities for the best localization performance. This thesis reviews current developments in the endeavors of nonlinear observability analyses as well as …

Ballasting System For An Autonomous Underwater Vehicle, Noura Rayes, Bahram Nassersharif, Zach Champney, Kyle Alessandro, Jason Mirandou

Senior Honors Projects

NOURA RAYES (Mechanical Engineering); Ballasting System for an Autonomous Underwater Vehicle Sponsor: Bahram Nassersharif (Mechanical Engineering)

Over the last year, our Mechanical Engineering Capstone team, Nautilus, has been working to design a ballasting system for various Autonomous Underwater Vehicles (AUVs) sponsored by Raytheon Technologies. Common AUV systems are used for a wide range of applications from environmental monitoring, oceanic exploration, to data collection. AUVs also have many technical advantages that make underwater tasks more efficient, cost-effective, and generally safer. Raytheon Technology, specifically, is looking to improve their existing ballasting mechanism for their AUVs to use for military defense. For this …

Detection Of Diffuse Sea Floor Venting Using Structured Light Imaging, Gabrielle Inglis, Clara Smart, Christopher Roman, Steven Carey

Graduate School of Oceanography Faculty Publications

Efficiently identifying and localizing diffuse sea floor venting at hydrothermal and cold seep sites is often difficult. Actively venting fluids are usually identified by a temperature induced optical shimmering seen during direct visual inspections or in video data collected by vehicles working close to the sea floor. Relying on such direct methods complicates establishing spatial relations between areas within a survey covering a broad area. Our recent work with a structured light laser system has shown that venting can also be detected in the image data in an automated fashion. A structured light laser system consists of a camera and …

Remote Analysis Of Grain Size Characteristic In Submarine Pyroclastic Deposits From Kolumbo Volcano, Greece, Clara Smart, D. P. Whitesell, Christopher N. Roman, Steven Carey

Graduate School of Oceanography Faculty Publications

Grain size characteristics of pyroclastic deposits provide valuable information about source eruption energetics and depositional processes. Maximum size and sorting are often used to discriminate between fallout and sediment gravity flow processes during explosive eruptions. In the submarine environment the collection of such data in thick pyroclastic sequences is extremely challenging and potentially time consuming. A method has been developed to extract grain size information from stereo images collected by a remotely operated vehicle (ROV). In the summer of 2010 the ROV Hercules collected a suite of stereo images from a thick pumice sequence in the caldera walls of Kolumbo …

Concept Tests For A New Wire Flying Vehicle Designed To Achieve High Horizontal Resolution Profiling In Deep Water, Chris Roman, Dave Hebert

Graduate School of Oceanography Faculty Publications

Efficiently profiling the water column to achieve both high vertical and horizontal resolution from a moving vessel in deep water is difficult. Current solutions, such as CTD tow-yos, moving vessel profilers, and undulating tow bodies, are limited by ship speed or water depth. As a consequence, it is difficult to obtain oceanographic sections with sufficient resolution to identify many relevant scales over the deeper sections of the water column. This paper presents a new concept for a profiling vehicle that slides up and down a towed wire in a controlled manner using the lift created by wing foils. The wings …

Development Of High Resolution Sea Floor Mapping Tools And Techniques, Gabrielle Inglis, J. Ian Vaughn, Clara Smart, Christopher N. Roman

Graduate School of Oceanography Faculty Publications

There is a persistent need for high resolution photographic and bathymetric maps of the sea floor for many research areas in marine geology, biology and archaeology. This poster will present recent work using high frequency multibeam sonars, stereo vision and structured light laser imaging techniques to create maps with centimeter resolution for these applications. This research involves the development of new image and sonar processing techniques that combat the typical difficulties of imperfect navigation information, limited sensor ranges and adverse environmental conditions associated with using marine robotic vehicles in the ocean. Data for this work has been collected with the …

Autonomous Underwater Vehicles As Tools For Deep-Submergence Archaeology, Christopher N. Roman, Ian Roderick Mather

Graduate School of Oceanography Faculty Publications

Marine archaeology beyond the capabilities of scuba divers is a technologically enabled field. The tool suite includes ship-based systems such as towed side-scan sonars and remotely operated vehicles, and more recently free-swimming autonomous underwater vehicles (AUVs). Each of these platforms has various imaging and mapping capabilities appropriate for specific scales and tasks. Broadly speaking, AUVs are becoming effective tools for locating, identifying, and surveying archaeological sites. This paper discusses the role of AUVs in this suite of tools, outlines some specific design criteria necessary to maximize their utility in the field, and presents directions for future developments. Results are presented …

Application Of Structured Light Imaging For High Resolution Mapping Of Underwater Archaeological Sites, Chris Roman, Gabrielle Inglis, James Rutter

Graduate School of Oceanography Faculty Publications

This paper presents results from recent work using structured light laser profile imaging to create high resolution bathymetric maps of underwater archaeological sites. Documenting the texture and structure of submerged sites is a difficult task and many applicable acoustic and photographic mapping techniques have recently emerged. This effort was completed to evaluate laser profile imaging in comparison to stereo imaging and high frequency multibeam mapping. A ROV mounted camera and inclined 532 nm sheet laser were used to create profiles of the bottom that were then merged into maps using platform navigation data. These initial results show very promising resolution …

Development Of A New Lagrangian Float For Studying Coastal Marine Ecosystems, Alex Schwithal, Chris Roman

Graduate School of Oceanography Faculty Publications

This paper presents an overview and initial testing results for a shallow water Lagrangian float designed to operate in coastal settings. The presented effort addresses the two main characteristics of the shallow coastal environment that preclude the direct of use of many successfully deep water floats, namely the higher variation of water densities near the coast compared with the open ocean and the highly varied bathymetry. Our idea is to develop a high capacity dynamic auto-ballasting system that is able to compensate for the expected seawater density variation over a broad range of water temperatures and salinities while using measurements …

The 2005 Chios Ancient Shipwreck Survey: New Methods For Underwater Archaeology, Brendan P. Foley, Katerina Dellaporta, Dimitris Sakellariou, Brian S. Bingham, Richard Camilli, Ryan M. Eustice, Dionysis Evagelistis, Vicki Lynn Ferrini, Kostas Katsaros, Dimitris Kourkoumelis, Aggelos Mallios, Paraskevi Micha, David A. Mindell, Christopher Roman, Hanumant Singh, David S. Switzer, Theotokis Theodoulou

Graduate School of Oceanography Faculty Publications

In 2005 a Greek and American interdisciplinary team investigated two ship wrecks off the coast of Chios dating to the 4th-century B.C. and the 2nd/lst century. The project pioneered archaeological methods of precision acoustic, digital image, and chemical survey using an autonomous underwater vehicle (AUV) and in-situ sensors, increasing the speed of data acquisition while decreasing costs. The AUV recorded data revealing the physical dimensions, age, cargo, and preservation of the wrecks. The earlier wreck contained more than 350 amphoras, predominantly of Chian type, while the Hellenistic wreck contained about 40 Dressel 1C amphoras. Molecular biological analysis of two amphoras …

Deep Sea Underwater Robotic Exploration In The Ice-Covered Arctic Ocean With Auvs, Clayton Kunz, Chris Murphy, Richard Camilli, Hanumant Singh, John Bailey, Ryan M. Eustice, Chris Roman, Michael Jakuba, Claire Willis, Taichi Sato, Ko-Ichi Nakamura, Robert A. Sohn

Graduate School of Oceanography Faculty Publications

The Arctic seafloor remains one of the last unexplored areas on Earth. Exploration of this unique environment using standard remotely operated oceanographic tools has been obstructed by the dense Arctic ice cover. In the summer of 2007 the Arctic Gakkel Vents Expedition (AGAVE) was conducted with the express intention of understanding aspects of the marine biology, chemistry and geology associated with hydrothermal venting on the section of the mid-ocean ridge known as the Gakkel Ridge. Unlike previous research expeditions to the Arctic the focus was on high resolution imaging and sampling of the deep seafloor. To accomplish our goals we …

Byzantium Beneath The Black Sea, Bridget Buxton, Robert Ballard, Michael Brennan, Dwight Coleman, Katy Croff, Christopher Roman, Dan Davis, Dennis Piechota, Sergiy Voronov

Graduate School of Oceanography Faculty Publications

This poster reports on the August 2007 Black Sea Expedition of the Institute for Archaeological Oceanography at the University of Rhode Island (IAO) and the Institute for Exploration (IFE), in collaboration with the Department of the Underwater Heritage of Ukraine. This year’s work marks a new phase in a multi-year (2000–2012) archaeological and oceanographic survey of the Black Sea. 2007 fieldwork focuses on two Byzantine shipwrecks. The 10th century C.E. shipwreck Chersonesos A (discovered in 2006) lies at 140 m depth in the suboxic zone off the Crimean peninsula. The ship carried a cargo of one-handled jars of a widely …

Robust Course-Boundary Extraction Algorithms For Autonomous Vehicles, Chris Roman, Charles Reinholtz

Graduate School of Oceanography Faculty Publications

Practical autonomous robotic vehicles require dependable methods for accurately identifying course or roadway boundaries. The authors have developed a method to reliably extract the boundary line using simple dynamic thresholding, noise filtering, and blob removal. This article describes their efforts to apply this procedure in developing an autonomous vehicle.