(2008) Zakaria - Prediction of Added Resistance of Ships by 3-D Green Function Method and its Comparision with Semi-3-D and 2-D Approaches

N M G Zakaria, Prediction of Added Resistance of Ships by 3-D Green Function Method and its Comparision with Semi-3-D and 2-D Approaches, IE(I) Journal – MR Vol 88, January 2008

Prediction of Added Resistance of Ships by 3-D Green Function Method and its Comparision with Semi-3-D and 2-D Approaches
N M G Zakaria [Department of Navel Architecture and Marine Engineering, Bangladesh University of Engineering and Technology, , Dhaka]

This paper was received on June 22, 2007. Written discussion on the paper will be entertained till March 31, 2008

ABSTRACT
Prediction of added resistance plays an important role in many applications in sea-keeping. It has been observed that among the existing methods of calculating added resistance, 2-D strip theory based classical methods are very popular. Although prediction given by these classical methods are reasonable at least from their practical point of view from conventional medium to high speed ship, but some of their inherent limitations fail to provide reasonable results for blunt ship forms which are usually slow speed ships. Conceiving the fact that there are huge financial activities involved for these particular blunt type of ships, for example, bulk carriers, tankers etc in the transportation sector of world economy, their accurate prediction of sea-keeping parameters deserves special attention for an economically optimum design. This paper presents numerical results of added resistance for some fine to blunt type ships using 3-D Green Function method. Before solving motion equations, hydrodynamic forces for surface ship advancing in waves at constant speed have been calculated and the method is then used to calculate total potential and its derivatives in order to achieve the final goal of predicting the added resistance of ships in waves using 3-D near field approach. The application of this approach in sea-keeping problems of some real hull form ships has been described and comparison with experimental and numerical results, given by other 2-D and semi 3-D approaches, demonstrate that 3-D approach is valid in predicting added resistance of ship in waves and also provides better results in many cases particularly for blunt shaped slow speed vessel.

KEYWORDS
2-D strip theory; 3-D Green Function; Hull boundary; Heave and pitch response

Source :The Institution of Engineers (India)

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