著者

INUI Takao KAJITANI Hisashi NARITA Hideaki MORI Kazuhiro

出版者

公益社団法人日本船舶海洋工学会

雑誌

Selected papers from the journal of the Society of Naval Architects of Japan

巻号頁・発行日

vol.9, pp.49-64, 1972-03

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A set of three 2m models (M-8, 9, 10) are wave-analyzed, where importance is placed in the bow wave analysis (Part I) rather than in the resultant wave analysis (Part. II). The models are generated from the central vertical plane distribution of sources m(ξ,ζ), whose draftwise distribution is varied as U, V and Λ types under the restriction of ∫^1_0m(ξ) =m(ξ,ζ)dζ=fixed. The results obtained are as follows: Part I-Bow Wave Analysis: (1) The "measured" bow wave patterns show not only the parallel shift (Δx, Δy) but also the "local" distortion in co-ordination to the "calculated" wave patterns where Δy is roughly estimated as B/2. (2) The "measured" bow wave amplitude A_F(θ) is found smaller than the "calculated" amplitude throughout the whole range ofθ=0〜π/2. (3) The comparison among the three tested models shows that the linearized theory does not work so well as far as the frameline effect is concerned. This may suggest a need of some kind of empirical correction factor α_2(ζ) to be applied for the "wave-making" strength of sources, such as 0 < α_2(ζ)&ltlarr;- 1, for 0 &ltlarr;-ζ&ltlarr;- 1 withα_2(0)<1 ,α_2(1)= 1 , whereζ=f/T (f = immersion of source, T = draft of distribution plane). Part II-Resultant Wave Analysis: (1) The resultant of bow and stern waves of Model M-8, the proto-type, is wave-analyzed. (2) Newman's truncation formula is not valid except y=0. (3) The effect of finite transverse separation (y) is of less importance than the truncation error. (4) A remarkable discrepancy is observed between "measured" and "calculated" wave amplitudes, particularly in the smaller range of θor the transverse wave component. (5) Beside viscosity effect, sheltering effect is supposed to be the cause for this discrepancy.