Airwakes are shed behind the ship’s superstructure and represent a highly turbulent and rapidly distorting flow field. This flow field severely affects pilot’s workload and such helicopter shipboard operations. It requires both the one-point statistics of autospectrum and the two-point statistics of coherence (normalized cross-spectrum) for a relatively complete description. Recent advances primarily refer to generating databases of flow velocity points through experimental and computational fluid dynamics (CFD) investigations, numerically computing autospectra along with a few cases of cross-spectra and coherences, and developing a framework for extracting interpretive models of autospectra in closed form from a database along with an application of this framework to study the downwash effects. By comparison, relatively little is known about coherences. In fact, even the basic expressions of cross-spectra and coherences for three components of homogeneous isotropic turbulence (HIT) vary from one study to the other, and the related literature is scattered and piecemeal. Accordingly, this dissertation begins with a unified account of all the cross-spectra and coherences of HIT from first principles. Then, it presents a framework for constructing interpretive coherence models of airwake from a database on the basis of perturbation theory. For each velocity component, the coherence is represented by a separate perturbation series in which the basis function or the first term on the right-hand side of the series is represented by the corresponding coherence for HIT. The perturbation series coefficients are evaluated by satisfying the theoretical constraints and fitting a curve in a least squares sense on a set of numerically generated coherence points from a database. Although not tested against a specific database, the framework has a mathematical basis. Moreover, for assumed values of perturbation series constants, coherence results are presented to demonstrate how coherences of airwakes and such flow fields compare to those of HIT. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2020. / FAU Electronic Theses and Dissertations Collection

This research is a preliminary design and feasibility analysis of a new type of shipboard electrical distribution system for Naval vessels. The design combines three traditionally separate disciplines: damage control, marine engineering, and electric power engineering to produce a hybrid system well suited for present and future surface warship environments. The design structure is a combination of shore-based power utility and shipboard distribution. The primary section is an interconnected bus feeder ring which resembles a shipboard vertical loop firemain. The bus feeder ring emulates the firemain’s network structure because it is well suited for both normal and emergency operating conditions. The distribution ring is used to transfer power between fire zones to load centers which radially feed loads within each zone. The electrical feasibility of the system was established through standard power system load flow contingency analysis, use of Navy design specifications, and direct comparison with an icebreaker radial electrical system. The new system could best be applied to small ships where the effective use of zone distribution is difficult, or where automation is needed to implement reduced manning. For large ships, this system would provide additional design alternatives which could help to reduce intersystem design interference where the requirements for one system impinge on those of another. As a final point, this system provides a viable network for facilitating the application of shore-based automatic switching technology to Naval vessels. / Master of Science

A procedure to generate an approximate bifurcation diagram for a single-degree-of-freedom system in a selected parameter space is developed. The procedure is based on the application of Floquet analysis to determine the stability of second-order perturbation approximations of the solutions of the system in the neighborhoods of specific resonances. As a control parameter is varied, a combination of elementary concepts of bifurcation theory and the proposed method are used to detect the first bifurcation from the periodic solutions and hence infer the qualitative changes that the system experiences. Codimension-one bifurcations are investigated in a two-dimensional parameter space composed of the amplitude and frequency of the excitation. The behavior of a softening Duffing oscillator is analyzed under external and parametric excitation. The dynamics of a ship rolling in waves is also considered and three types of excitations are treated: external, parametric, and a combination of both. Analog- and digital-computer simulations are used to verify the accuracy of the analytical predictions. It is found that the predictions based on the first bifurcation of the analytical solution give a good estimate of the actual behavior of the system. The stability regions of the solutions near each of the resonances display a self-similar structure in the parameter space. The physical implications of these bifurcation patterns are important for the prediction of the capsizing of ships. The dangerous regions of the parameter space where capsizing might occur are identified for a given system. Capsizing is found to occur via two distinct scenarios: one evolving from a large oscillation through a disappearance of a chaotic attractor (crises) and a second, potentially more dangerous, developing from a small oscillation through a sudden tangent instability. These scenarios agree with previous experimental studies. / Ph. D.

No description available.

Thesis (Ocean E)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1980. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by Joseph Anthony Carnevale, Jr. / Ocean E

Abstract not available

In 1973, researchers from the Institute of Nautical Archaeology (INA) were led to the site of a wrecked ship by sponge diver Mehmet A??k??n, near his hometown of Bozburun, Turkey. During further monitoring over the following 21 years by INA, the site was identified as a merchant vessel dating from the 9th century AD. The excavation of the site by INA researchers and students from Texas A&M University occurred over four summer seasons, from 1995 to 1998, and yielded approximately 900 whole or nearly-whole amphorae, personal items, palynological material, and approximately 35 percent of the vessel??s wooden hull. This dissertation is a record of the curation, cataloging, analysis and re-assembly of the preserved elements of the Bozburun vessel??s hull, as well as a theoretical reconstruction of the entire vessel. The Bozburun vessel is unique as it is the only fully-excavated shipwreck from the 9th century AD, and is, indeed, a valuable source of examples of ship construction in the Mediterranean between the 7th and the 11th centuries AD. This dissertation, after discussing the methods of excavation and cataloging methods, posits the hypothesis that the techniques used to build this vessel represent a transitional stage in shipbuilding technology, combining distinctly old and new techniques. While the builders used embedded edge joinery in the ship??s planking, a very old method, they also appear to have used a conceptual framework and standards to design the vessel as well; methods evident in modified forms in Italian shipbuilding treatises from the Renaissance.

In 1973, researchers from the Institute of Nautical Archaeology (INA) were led to the site of a wrecked ship by sponge diver Mehmet A??k??n, near his hometown of Bozburun, Turkey. During further monitoring over the following 21 years by INA, the site was identified as a merchant vessel dating from the 9th century AD. The excavation of the site by INA researchers and students from Texas A&M University occurred over four summer seasons, from 1995 to 1998, and yielded approximately 900 whole or nearly-whole amphorae, personal items, palynological material, and approximately 35 percent of the vessel??s wooden hull. This dissertation is a record of the curation, cataloging, analysis and re-assembly of the preserved elements of the Bozburun vessel??s hull, as well as a theoretical reconstruction of the entire vessel. The Bozburun vessel is unique as it is the only fully-excavated shipwreck from the 9th century AD, and is, indeed, a valuable source of examples of ship construction in the Mediterranean between the 7th and the 11th centuries AD. This dissertation, after discussing the methods of excavation and cataloging methods, posits the hypothesis that the techniques used to build this vessel represent a transitional stage in shipbuilding technology, combining distinctly old and new techniques. While the builders used embedded edge joinery in the ship??s planking, a very old method, they also appear to have used a conceptual framework and standards to design the vessel as well; methods evident in modified forms in Italian shipbuilding treatises from the Renaissance.

Thesis (M.S.)--Florida State University, 2004. / Advisor: Dr. Cheryl Ward, Florida State University, College of Arts and Sciences, Department of Anthropology. Title and description from dissertation home page (June 17, 2004). Includes bibliographical references.

This Thesis will consider the development of the traditional bill of lading from its origins, which appear to be much older than previously considered, up to the present day. The development of the bill of lading will be examined in order to answer basic questions: what is a traditional bill of lading, and what functions does it perform. In Part I of the Thesis the development of the three main functions of the traditional bill will be considered, namely receipt, contract, document of title. It will conclude with observations on the nature of the traditional bill of lading and how it differs from the early form of the bill of lading. Part II of the Thesis will then consider the development and nature of related shipping documents (charterparty bills, received for shipment bills, non-transferable bills), how far these documents perform the functions of the traditional bill of lading, and whether they can be truly described as bills of lading. Part II will then go on to consider the development and nature of electronic bills of lading and assess how well such bills perform the functions of the traditional bill of lading. The Thesis will conclude that although most of the functions of the traditional bill are in effect performed by electronic bills, electronic bills are in fact a new type of bill of lading and not merely a traditional bill in an electronic format. Conclusions will then be drawn as to what effect the development of new types of bill of lading will have on the future of the traditional bill of lading in the maritime industry.