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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Hydrodynamics of advanced high-speed sealift vessels.

Lazauskas, Leo V. January 2005 (has links)
There is at present great interest in large ships capable of carrying substantial cargo at speeds in excess of 40 knots. At the same time, there are large gaps in our understanding of the hydrodynamics, structural engineering, and economics of high-speed vessels. Monohulls, catamarans, trimarans, surface effect ships, and air cushion vehicles are considered in the present work. The total resistance of these vehicles is divided into separate components which are estimated using different methods. Skin-friction is estimated using Grigson's algorithm which gives much better predictions of flat plate skin-friction than the traditional ITTC method. Wave resistance of displacement hulls is estimated using Michell's thin-ship theory: a similar theory is used for the wave resistance of travelling pressure distributions. Several simple formulae are derived that can be used in the preliminary design stage of catamarans to estimate optimum demihull separation. Memetic algorithm techniques are used to find vessels with minimum (calm-water) total resistance. Optimal geometric parameters are found for vessels of 1200 tonnes under a variety of geometric limitations and constraints on upright stability, at design speeds of 50 knots and 75 knots. Estimates are made of the principal weight components of the optimal vessels. Empirical formulae for the efficiencies of powerplants and propulsors then enable estimates to be made of the maximum range, the cargo capacity, and the fuel consumption. / Thesis (M.Sc.)--School of Mathematical Sciences, 2005.
2

Identification of the hydrodynamic model of an underwater robotic vehicle heaving and pitching near the sea surface using its measured response /

Mahfouz, Ayman B., January 2001 (has links)
Thesis (Ph.D.)--Memorial University of Newfoundland, 2001. / Bibliography: leaves 187-194.
3

Wave making resistance characteristics of trimaran hulls /

Elcin, Zafer. January 2003 (has links) (PDF)
Thesis (M.S. in Mechanical Engineering)--Naval Postgraduate School, December 2003. / Thesis advisor(s): Fotis Papoulias. Includes bibliographical references (p. 73). Also available online.
4

Hydrodynamics of advanced high-speed sealift vessels.

Lazauskas, Leo V. January 2005 (has links)
There is at present great interest in large ships capable of carrying substantial cargo at speeds in excess of 40 knots. At the same time, there are large gaps in our understanding of the hydrodynamics, structural engineering, and economics of high-speed vessels. Monohulls, catamarans, trimarans, surface effect ships, and air cushion vehicles are considered in the present work. The total resistance of these vehicles is divided into separate components which are estimated using different methods. Skin-friction is estimated using Grigson's algorithm which gives much better predictions of flat plate skin-friction than the traditional ITTC method. Wave resistance of displacement hulls is estimated using Michell's thin-ship theory: a similar theory is used for the wave resistance of travelling pressure distributions. Several simple formulae are derived that can be used in the preliminary design stage of catamarans to estimate optimum demihull separation. Memetic algorithm techniques are used to find vessels with minimum (calm-water) total resistance. Optimal geometric parameters are found for vessels of 1200 tonnes under a variety of geometric limitations and constraints on upright stability, at design speeds of 50 knots and 75 knots. Estimates are made of the principal weight components of the optimal vessels. Empirical formulae for the efficiencies of powerplants and propulsors then enable estimates to be made of the maximum range, the cargo capacity, and the fuel consumption. / Thesis (M.Sc.)--School of Mathematical Sciences, 2005.
5

Analysis of ship flow in an ideal fluid using Guilloton's method and spline functions /

Chuang, Jiunn-Ming, January 1984 (has links)
Thesis (M.Eng.) -- Memorial University of Newfoundland. / Bibliography : leaf 48. Also available online.
6

Characterizing the relative velocity of seagrass blades under oscillatory flow conditions and the implications for wave attenuation

Bradley, Brian Kevin. January 2007 (has links)
Thesis (M.S.)--University of West Florida, 2007. / Title from title page of source document. Document formatted into pages; contains 69 pages. Includes bibliographical references.
7

Methods for removing inertial force from measured wave impact force signals /

Winsor, Fraser N., January 2000 (has links)
Thesis (M.Eng.)--Memorial University of Newfoundland, 2000. / Bibliography: leaves [194-197].
8

Interaction of extreme ocean waves with offshore structures

Walker, Daniel Anthony Guy January 2006 (has links)
With most of the world's untouched oil and gas resources offshore and the possibility that hurricanes are becoming more frequent and more intense, the risks associated with offshore oil and gas production are increasing. Therefore, there is an urgent need to improve current understanding of extreme ocean waves and their interaction with structures. This thesis is concerned with the modelling of extreme ocean waves and their diffraction by offshore structures, with the ultimate aim of proposing improved tools for guiding airgap design. The feasibility of using linear and second order diffraction solutions with a suitable incident wave field to predict extreme green water levels beneath multi-column structures is investigated. Such tools, when fully validated, could replace the need to carry out model tests during preliminary design. When contemplating airgap design it is crucially important that consideration is given to the largest waves in a sea state, the so-called freak or rogue waves. This thesis studies the nature of one specific freak wave for which field data is available, namely the Draupner New Year wave. Unique features of this wave are identified, distinguishing it from a typical large wave, and an estimate of the probability of occurrence of the wave is given. Furthermore, a design wave, called NewWave, is proposed as a good model for large ocean waves and is validated against field and experimental data. The diffraction of regular waves and NewWaves by a number of structural configurations is studied. In order to assess the validity of using diffraction solutions for the purposes of airgap design, comparisons are made with measured wave data from a programme of wave tank experiments. Wave data for a real platform configuration are examined to highlight the key issues complicating the validation of diffraction based design tools for real structures. The ability of diffraction theory to reproduce real wave measurements is discussed. The phenomenon of near-trapping is also investigated, allowing guidelines for airgap design to be established.
9

An analysis of wave forces on prototype walls under tsunami loading /

Oshnack, Mary Elizabeth. January 1900 (has links)
Thesis (M.Oc.E.)--Oregon State University, 2010. / Printout. Includes bibliographical references. Also available on the World Wide Web.
10

Identification of the variance of the wave exciting rolling moment using ship's random response /

Xing, Zhiliang, January 2003 (has links)
Thesis (M.Eng.)--Memorial University of Newfoundland, 2003. / Bibliography: leaves 76-78. Also available online.

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