著者

岡畑 豪 藪下 和樹

出版者

公益社団法人 日本船舶海洋工学会

雑誌

日本船舶海洋工学会論文集 (ISSN:18803717)

巻号頁・発行日

vol.26, pp.17-25, 2017 (Released:2018-03-03)

参考文献数

27

被引用文献数

2

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We present a new method determining a form factor from resistance test results. The total resistance coefficient is approximated by a straight line and a polynomial expression in the present method. The straight line and the polynomial expression represent a viscous resistance and a wave-making resistance, respectively. It is shown that existing flat plate friction formulae are expressed as straight lines, and its inclination is only a function of the form factor. We determine the inclination (form factor) and coefficients of the polynomial expression by means of a linear least-squares method. The features of the present method are that: the form factor is decided without extrapolation; all measured data of resistance testing can be used in this analysis, although low-speed range data should be selected in the Prohaska's method. Using the ITTC57 correlation line, the values of the form factors obtained by the present method are almost the same as by Prohaska's method. It is found that the influence of the unreliable extra low-speed range data in the present method is less than in the Prohaska's method.

著者

井上 真一 佐々木 紀幸 村上 恭二 藪下 和樹 鈴木 勝雄

出版者

The Japan Society of Naval Architects and Ocean Engineers

雑誌

日本造船学会論文集 (ISSN:05148499)

巻号頁・発行日

vol.1996, no.180, pp.1-11, 1996 (Released:2009-09-16)

参考文献数

10

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The amplitude functions measured by wave analysis experiment for a ship model are expanded in Mathieu function series in order to obtain the informations of improving the hull form. The expansion gives sectional area curve of the model as assumed as a source generating the measured wave system in linear wave-making theory. The expansion coefficients correspond with the coefficients of Mathieu expansion of the assumed sectional area curve and give the strengths of wave pattern resistance components. In order to reduce the total wave resistance the sectional area curve components corresponding with the dominant wave resistance components is to be subtracted.The amplitude functions measured for three ship models are expanded in Mathieu function series and their wave resistance components are compared with each other at various Froude numbers. The direction of improving hull form obtained by the present method corresponds with the design philosophy of the three ship forms.