著者
乾 崇夫 高幣 哲夫
出版者
The Japan Society of Naval Architects and Ocean Engineers
雑誌
造船協會論文集 (ISSN:18842062)
巻号頁・発行日
vol.1961, no.110, pp.75-89, 1961 (Released:2009-07-23)
参考文献数
12

今春3月, 瀬戸内海航路高速客船くれない丸を供試船として, Waveless船型理論にもとづく超大型バルブの「船首波打消し」の実船試験が行なわれた。今回これを「水槽試験」・「実船試験」・「波形観測」の3篇にわけて報告する。以下はその第1部 (前篇) 「水槽試験」の報告であるが, ここでは他の2篇と異なり, 記述の範囲を今回行なわれた実船試験のみに限定しないで, くれない丸の計画当初から現船型決定の経緯にまでさかのぼり, くれない丸がその計画・建造・就航・実船試験の各時点において東大水槽におけるWaveless船型理論の発展の経過といかに交渉しあつたかをあきらかにすることに意を用いた。Waveless船型理論では在来の水槽試験のほかに, 「波形分析」という新しい船型学的手法を重視する。今回も当然模型・実船の両方についてこの「波形分析」が試みられたが, この部分は一括して第3部 (後篇) 「波形観測」で取扱われている。なお, 第2部 (中篇) 「実船試験」では, 中心となる速力試験のほかにZ操船試験と旋回試験とにもふれられている。
著者
乾 崇夫 菊池 義男 岩田 達三
出版者
The Japan Society of Naval Architects and Ocean Engineers
雑誌
造船協會論文集 (ISSN:18842062)
巻号頁・発行日
vol.1956, no.100, pp.35-45, 1956 (Released:2009-09-16)
参考文献数
27
被引用文献数
2

Since 1944, when one of the present Authors (INUI) and his collaborator calculated mathematically the wave-making resistance of ships in a shallow sea, necessity has long been recognized for making further quantitative investigations regarding to the practical adaptability of the theory. The following notes are aimed for clarifying the still remained question to what extent such a linearized wave-making theory can be safely applied in cases of a restricted water (b=h=finite) as well as a shallow water (h=finite, b=infinitive), where h denotes the depth of a water, b the width.A 1.750 m mathematical model S-201, whose equivalent source distribution is known, is towed in the Tokyo University Tank at the depth of water h/L=1.371, 0.400, 0.300 and 0.200.Comparatively good coincidence has been obtained between the calculated and measured wavemaking resistance, excluding the narrow critical range of Fh=0.820.95 where the KREITNER'S non-linear restricted water effect is clearly observed especially at the shoalest depth h/L=0.200.
著者
乾 崇夫 菊池 義男 岩田 達三
出版者
The Japan Society of Naval Architects and Ocean Engineers
雑誌
造船協會論文集 (ISSN:18842062)
巻号頁・発行日
vol.1956, no.100, pp.47-67, 1956 (Released:2010-01-25)
参考文献数
12

The wave profile measurements are made with two wall-sided, deep-drafted mathematical models (S-103, S-203) by applying the chemical film method, where the Benzoic Acid is effectively used for the first time, and found as pre-eminently suited to contrasting the flow phenomena on ship models such as wave profiles, initial still water lines, stream lines, and laminar flow area.Comparisons are also made between the calculated and the observed wave profiles.Coincidence is good along the models, but is unsatisfactory in the rear.The principal cause might be safely ascribed to the fact that the wake intesity is always extinguishedly strong just on the narrow band in the vertical symmetrical plane (y=0).Conclusions are then drawn that the present field of the mentioned comparisons between the theory and the observation must be extended from one dimension (on the line y=0, exclusively) to two dimensions, to which the photographic measurements by stereograph might be expected as essential.
著者
高幣 哲夫 乾 崇夫
出版者
The Japan Society of Naval Architects and Ocean Engineers
雑誌
造船協會論文集 (ISSN:18842062)
巻号頁・発行日
vol.1961, no.110, pp.105-118, 1961 (Released:2009-07-23)
参考文献数
8

この報告は, 今春行なわれたくれない丸の大型バルブによる船首波打消しの実船実験およびこれに先立つて行なわれた東大の2.5m模型水槽試験のうち, 波形分析という新しい船型学的研究方法を適用した部分について述べたものである。
著者
下村 芳弘 北沢 孝宗 乾 崇夫 梶谷 尚
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.1979, no.146, pp.27-34, 1979 (Released:2009-09-04)
参考文献数
12

The low speed wave resistance theory developed by Baba4) and Maruo5) seems to be a promising theory to predict the wave resistance of conventional ships, because it includes the nonlinear effect of the free surface condition. The wave resistance curves calculated by the low speed theory, however, have large humps and hollows, and they do not agree with the measured7) 10) .In this paper, a refinement of the low speed theory is discussed by imposing the more accurate hull surface condition. The wavy source distribution added to satisfy the hull sruface condition is obtained numerically, and the wave resistance, the hull side wave profiles and the velocities around the hull surface are evaluated. The results coincide fairly well with the measured values, especially the humps and the hollows of the calculated wave resistance curves are remarkably reduced.It is ascertained that the added source distribution plays an important role to improve the low speed wave resistance theory, in spite that its strength is one-order smaller than that of the double model source.
著者
乾 崇夫 高幣 哲夫 熊野 道雄
出版者
The Japan Society of Naval Architects and Ocean Engineers
雑誌
造船協會論文集 (ISSN:18842062)
巻号頁・発行日
vol.1960, no.108, pp.39-51, 1960 (Released:2009-09-16)
参考文献数
29
被引用文献数
2

As to the wave-interference phenomena connected with the bulb there have been presented two kinds of explanations : one being theoretical, and the other practical.Following the theoretical explanation, which is largely indebted to Havelock and Wigley, we may assume that the wave-making characterististics of the bulbous bow can be safely represented by an isolated point doublet. If admitted, this goes at once to the conclusion that the free wave patterns due to the fitted bulb can be intentionally put just in inverse phase or with strictly half wave-length difference against the main hull waves. This is nothing but the most desirable situation for us in view of promoting the maximum interfering merits of the bulb.On the contrary, the other explanation enforces, rather practically, too much importance of the virtual increment in the wave-making length of the hull which is caused by the bulb waves. In this way, it has long been believed that the reduced wave-making resistance accompanying the bulbous bow has much to do with its increased “effective wave-making length”. From this standpoint of view, it is suggested that, when any amount of bulb merit observed, the bulb waves must proceed by some intermediate fraction between 1/41/2 of ship wave length against the main hull waves. This means that from the bulbous bow we can expect only an incomplete interfering merit at the best.This report is aimed for the experimental determination of the existing conflict, mentioned above, with regard to the 'actual' phase-difference between the bulb waves and the hull waves. The wave analysis procedure is applied for the first time. The conclusion is that the theoretical treatment of the bulb which is introduced by Havelock and Wigley can be practically approved. A few remarks are also made on the two different phases of the hydrodynamical characteristics of the bulbous bow. Its corresponding system of singularities is represented by the combination of an isolated doublet with a continuous source distribution.The former has a positive and therefore the same sense with the latter in hull form characteristics, but has a negative and therefore the reverse sense in wave-making characteristics. This is the true reason why the wavemaking resistance is sometimes reduced remarkably with the bulbous form whose displacement is larger by its bulb than the original form.