Date of Award

8-6-2009

Degree Type

Dissertation

Degree Name

Ph.D.

Degree Program

Engineering and Applied Science

Department

Naval Architecture and Marine Engineering

Major Professor

Vorus, William

Second Advisor

Birk, Lothar

Third Advisor

Wei, Dongming

Fourth Advisor

McCorquodale, J. Alex

Fifth Advisor

Akyuzlu, Kazim

Abstract

With the ever present desire for ships and boats to run faster while carrying a greater load, a need exists to reduce the drag while simultaneously increasing hydrodynamic lift. Therefore, a need for semi-planing/semi-displacement hullforms exists for vessels to carry relatively high loads (between 500 and 3000 tons) with a general length Froude number range between 0.4 and 1.0. A hybrid method for calculating the lift and drag of semi-planing/semi-displacement hull forms is developed. This is done by separating the kinematic boundary condition into odd and even parts. The odd and even parts of the kinematic boundary condition are solved independently along with the free-surface boundary condition and superimposed for a complete "hybrid" solution. The superimposed solution components relate to Michell's (1898) "thin ship" integral for odd flow and Maruo's (1967) "flat ship" integral for even flow. A generalized form of Michell's (1898) integral is provided for high speed slender bodies by implementing a more realistic near field condition (Ogilvie, 1975) and a wake trench (Vorus, 2009). A generalized form of Maruo's (1967) integral has also been developed. Comparisons of the generalized methods have been made with available model test and/or analytical data. With this, the concept of the Semihull (Vorus, 2005) is revisited. Some results are given concerning the validity of the Semihull as compared to a traditional displacement ship. Hull form optimization is also explored and the deadrise angle distribution proves to be a major factor in calm water hydrodynamic performance.

Rights

The University of New Orleans and its agents retain the non-exclusive license to archive and make accessible this dissertation or thesis in whole or in part in all forms of media, now or hereafter known. The author retains all other ownership rights to the copyright of the thesis or dissertation.

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