Ocean Engineering Commons^™

Model Based Adaptive Control Of Underwater Vehicles For Improved Ocean Science, Christopher J. Mcfarland

Link Foundation Ocean Engineering and Instrumentation Fellowship Reports

Recent advances in unmanned underwater vehicle (UUV) capabilities have enabled oceanographic scientists to consider addressing research topics previously thought impractical or impossible. One such topic is the validation of high resolution computer models; long term deployments of coordinated UUV survey teams have been proposed to collect the density of measurements required. Another topic is the study of biological diversity in volatile areas; UUV intervention/sampling deployments have been proposed because of the inherent risks. In general, providing a high density of high accuracy measurements requires passing many targets as quickly and closely as possible. Similarly, efficacy for intervention/sampling deployments requires agile …

Predicting Underwater Radiated Noise From Offshore Impact Pile Driving, Huikwan Kim

Link Foundation Ocean Engineering and Instrumentation Fellowship Reports

Offshore wind turbines have been installed throughout Europe and are expected to be built in the United States water shortly. Offshore wind is an attractive option because 53% of the nation’s population lives in coastal area where energy cost and demands are high. Offshore winds tend to blow harder and more uniformly than on land [1]. However, structure borne noise and vibration generated by offshore impact pile driving radiate into and propagate through the air, water, and sediment media. The objective of this project is quantitatively predicting noise level around the piling location at sea to estimate the effects of …

Re-Evaluation Of Resistance Prediction For High-Speed Round Bilge Hull Forms, Jae Won

Theses and Dissertations

Predicting the resistance of a high-speed monohull has been of interest to Naval Architects for several decades. Even though considerable amount of research has been carried out in this area, there remains a degree of uncertainty in the accurate resistance prediction in the early design stage. This research thesis attempts to investigate a method for enhancing the accuracy of resistance prediction methods for high-speed round-bilge monohull form vessels for a wide range of volumetric Froude numbers (Fn). While a number of systematic series are in existence, their data are either not readily available or scattered in various internal reports and …

Underwater Object Detection And Identification Using Distributed Pressure Sensors, Audrey Maertens

Link Foundation Ocean Engineering and Instrumentation Fellowship Reports

Underwater vision is usually limited. Object detection and identification is therefore one of the main challenges of underwater navigation. A new sensing modality, specifically developed for underwater environments, would greatly increase the scope of underwater missions. Taking inspiration from the lateral line of fish, I believe that pressure sensing can be a viable alternative to vision in order to detect and identify obstacles. Recent advances in the area of micro-engineering will soon enable to build sensors that match the size and mimic the functions and organization of the lateral line. However, little is known about how the pressure distribution along …

Advanced Underwater Vehicle Navigation, M. Jordan Stanway

Link Foundation Ocean Engineering and Instrumentation Fellowship Reports

Underwater vehicles–both manned and unmanned–are critical in our efforts to explore and study the depths of the ocean. Most underwater sensors possess a relatively small field of view; this means they must be carried over large distances to achieve high spatial coverage and resolution. The vast amount of data these sensors collect is much more valuable if the location of the vehicle is precisely known at the time the data is collected. This gives rise to the maxim: The data is only as good as the navigation. Navigation remains a challenging problem for underwater vehicles. Fundamental limitations of sensing technology …

Turbulence Measurement With Coherent Doppler Sonar, Jeremy Dillon

Link Foundation Ocean Engineering and Instrumentation Fellowship Reports

The ocean has been described as Earth's "fi nal frontier" in a vision statement on ocean exploration (National Oceanic and Atmospheric Administration, 2000). The search for new insight is motivated by the fact that our environmental and economic security depends critically on the ocean and the freshwater bodies that drain into it. As the vast majority of the ocean is unknown and unexplored, there is great potential for scientifi c discovery beneath the sea surface (McNutt, 2002). The development of remote and in situ sensors forms a cornerstone of this vision for exploring ocean dynamics at new scales.

Investigation And Modeling Of Ice Fracture In Cold Ocean Engineering Applications, Rocky S. Taylor

Link Foundation Ocean Engineering and Instrumentation Fellowship Reports

Ice conditions present a significant challenge in the design of ships and structures for the development of offshore energy resources in cold ocean environments. Many regions throughout the world including Alaska, Canada, Russia, Norway, Kazakhstan and China are developing offshore energy resources in ice-prone environments. The growth and stability of the global economy is closely linked to that of our energy supply, and offshore industrial activity in Northern regions has increased significantly in recent years. One of the most significant engineering challenges when designing structures for ice environments is the estimation of design ice loads. The design load scenario for …

Dynamics Of Wave-Current Boundary Layers Over Very Rough Boundaries, Marion Bandet-Chavanne

Link Foundation Ocean Engineering and Instrumentation Fellowship Reports

In this study, acoustic profiling techniques are used to resolve the two-dimensional spatial structures of the oscillating boundary layer in a phase-averaged sense over a wave orbital amplitude. The principal objective of this work is to examine the spatial variability of turbulent properties over irregular roughness. Field observations are used to investigate the interaction between bottom roughness, flow structure and turbulent properties within the near-bed flow. The overall focus of the research is to relate wave energy dissipation or friction factor estimates to physical roughness elements and understand the dynamics of such processes in the near-bed flow.

Semi-Autonomous Control Of Autonomous Underwater Vehicles, Stephen C. Martin

Link Foundation Ocean Engineering and Instrumentation Fellowship Reports

The goal of my graduate research is to address two engineering science problems whose solution will enable Autonomous Underwater Vehicles (AUVs) to routinely perform semi-autonomous missions presently considered impractical or infeasible. I am pursuing this research under the direction of Professor Whitcomb in the Dynamical Systems and Controls Laboratory at Johns Hopkins University, and in collaboration with the faculty of the Deep Submergence Laboratory of the Woods Hole Oceanographic Institution (WHOI).

In the last decade AUVs have begun to complement Human Occupied Vehicles (HOVs) and Remotely Operated Vehicles (ROVs) as effective platforms for oceanographic exploration. HOVs and ROVs are highly …

Performance Enhancement Of The Wirewalker Wave-Powered Profiler, Jonathan Pompa

Link Foundation Ocean Engineering and Instrumentation Fellowship Reports

The Wire-Walker is a wave-powered vertical profiler made for carrying oceanographic instruments. It cycles continuously through the depth range set by the user, providing a traveling platform for sensors. To achieve high data resolution in time varying environments, the Wire-Walker was redesigned from its original configuration for higher profiling speed. Improvements were made to the WireWalker profiler by using a numerical simulation of the system dynamics. Each physical parameter was varied in the model to find its effect on the profiling speed. Using the guidelines from the modeling experiment, a new WireWalker was constructed and tested in the ocean. The …

Methodology Evaluation For Remotely Estimating Water Quality Parameters In Estuarine Waters, Charles R. Bostater, Manuel Gimond

Ocean Engineering and Marine Sciences Faculty Publications

Water absorption signatures were measured from water samples placed in a 50 cm pathlength cylindrical cuvette. Quantitative analysis of chlorophyll-a and dissolved organic matter (DOM- humic acid, fulvic acid, or tannic acid) was conducted using second derivative spectra followed by computation of double inflection ratio (DIR) spectra for all possible combinations of bands (from 362-1 1 15 nm with 252 channels). A specially designed instrument system is described which allows measurements of absorption of particulate and dissolved organic matter (chlorophyll-a and DOM) in a water sample. The ability of the system to allow measurement of absorption signatures and relating the …