Thesis (M.C.E.)--University of Delaware, 2006. / Principal faculty advisor: Jack Puleo, Dept. of Civil & Environmental Engineer. Includes bibliographical references.

The shallow waters west of Scotland feature strong variability in water properties on a variety of temporal scales. While the region is known to be subject to both coastal and oceanic influences, the causes of variability are poorly understood. The limited characterisation of changes in coastal waters impacts our ability to explain the behaviour of coastal ecosystems, and predict their resilience to future climate scenarios. This thesis uses historical data in conjunction with recent cruises and a coastal mooring to investigate the causes of variability in the waters west of Scotland. Two new inter-annual salinity time series on the European shelf are developed. The spatial variability in salinity in shallow waters is greatest during winter and increases by a factor of four between the shelf edge and the coastline. At the shelf edge, new observations of the along-slope current suggest that it is stronger but less stable during winter, leading to a greater availability of oceanic water on the outer Malin Shelf. However unlike other documented shelf regions, shelf edge processes do not directly influence Scottish coastal water properties. A baroclinic current originating in the Irish Sea is the main influence near the Scottish coast during quiescent periods, but wind forcing dominates shelf processes during most winters, with prevailing winds tending to drive oceanic water towards the coast. While salinity in the Sea of the Hebrides is moderately correlated to wind, coastal salinity is sensitive to both advective processes and freshwater runoff. On inter-annual time-scales, salinity on the Malin Shelf is higher when the North Atlantic Oscillation (NAO) is positive, whereas the northern Irish Sea is fresher during a positive NAO state. Salinity and flow pathways in Scottish coastal waters appear to be resilient both to changes in the Rockall Trough and a warming climate on decadal time-scales.

No description available.

Thesis (M.C.E.)--University of Delaware, 2006. / Principal faculty advisors: Dominic M. Di Toro and James T. Kirby, Dept. of Civil & Environmental Engineering. Includes bibliographical references.

Thesis (M. S.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2010. / Committee Chair: Webster, Don; Committee Member: Sturm, Terry; Committee Member: Weissburg, Marc. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Thesis (Ph.D)--Civil and Environmental Engineering, Georgia Institute of Technology, 2010. / Committee Chair: Kevin A. Haas; Committee Member: Emanuele Di Lorenzo; Committee Member: Hermann M. Fritz; Committee Member: Paul A. Work; Committee Member: Terry W. Sturm. Part of the SMARTech Electronic Thesis and Dissertation Collection.

We deployed depth-specific drifters in the western and eastern parts of the South Arm basin of Lake Opeongo and collected zooplankton samples at west and east fixed stations and at additional up- and downwind locations at three depths of the epilimnion under a range of wind conditions. Water currents had highest association with the immediate wind direction and the direction they travelled was dependent on wind strength. Along the main west-east fetch large zooplankton resided high in the epilimnion and were transported eastwards by strong surface currents where they accumulated. Small zooplankton were more uniformly distributed with depth and their accumulation patterns and transport mechanisms are less clear. Along shorter fetches oriented off-angle with the main one accumulations of zooplankton occurred at all downwind locations under heavy winds although the patterns are more variable and complex. These downwind accumulations likely create high quality habitat for warm water fish.

The objective of this thesis is to analyze the flow past an ocean current turbine using a finite volume Navier-Stokes CFD solver. A full 3-D RANS approach in a moving reference frame is used to model the flow. By employing periodic boundary conditions, one-third of the flow-field is analyzed and the output is replicated to other sectors. Following validation of the computation with an experimental study, the flow fields and particle paths for the case of uniform and sheared incoming flows past a generic turbine with various blade pitch angles are evaluated and analyzed. Flow field and wake expansion are visualized. Eddy viscosity effects and its dependence on flow field conditions are investigated. / by Zaqie Reza. / Thesis (M.S.C.S.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.

The main objective of the thesis is to carry out a rigorous hydrodynamic analysis of ocean current turbines and determine power for a range of flow and geometric parameters. For the purpose, a computational tool based on the vortex lattice method (VLM) is developed. Velocity of the flow on the turbine blades, in relation to the freestream velocity, is determined through induction factors. The geometry of trailing vortices is taken to be helicoidal. The VLM code is validated by comparing its results with other theoretical and experimental data corresponding to flows about finite-aspect ratio foils, swept wings and a marine current turbine. The validated code is then used to study the performance of the prototype gulfstream turbine for a range of parameters. Power and thrust coefficients are calculated for a range of tip speed ratios and pitch angles. Of all the cases studied, the one corresponding to tip speed ratio of 8 and uniform pitch angle 20 produced the maximum power of 41.3 [kW] in a current of 1.73 [m/s]. The corresponding power coefficient is 0.45 which is slightly less than the Betz limit power coefficient of 0.5926. The VLM computational tool developed for the research is found to be quite efficient in that it takes only a fraction of a minute on a regular laptop PC to complete a run. The tool can therefore be efficiently used or integrated into software for design optimization. / by Aneesh Goly. / Thesis (M.S.C.S.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.

This study combines Optical Plankton Counter data on zooplankton abundance and Acoustic Doppler Current Profiler data on water currents to test hypotheses about spatial zooplankton distributions near a major point of land affecting local wind and water current patterns. Data were collected by repeatedly sampling a 2 km linear transect in the South Arm of Lake Opeongo, Ontario, Canada during July, 2008. Moving Split Window techniques were used to identify breakpoints in both zooplankton biomass concentration and a measure of water turbulence, and confirmed an effect of the topographic feature on local zooplankton distributions. Using additional data collected in 2001 and 2003, zooplankton abundance distributions were also tested under three wind speed ranges predicted from physical principles to correspond to varying stability of the water column. Significant differences were found in the variability and patch sizes of the distributions, indicating the importance of wind speeds on zooplankton patchiness.