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Article type: Cover
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Cover1-
Published: December 30, 1975
Released on J-STAGE: March 30, 2018
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Article type: Cover
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Cover2-
Published: December 30, 1975
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Article type: Appendix
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Published: December 30, 1975
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Masaru IKEDA
Article type: Article
Pages
1-10
Published: December 30, 1975
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As a series of studies on small high speed crafts, the data on aluminum, steel and FRP high speed passenger boats are presented in this paper.
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Masaaki KUROI
Article type: Article
Pages
11-18
Published: December 30, 1975
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A computer program for optimum ship routing is developed. Calculations of optimum ship route are carried out using the data of sea condition experienced by two high speed single-screw container ships, "America-Maru" and "Golden Gate Bridge" , that are placed on the Pacific South West line. The effectiveness of the computer program is verified by comparing the calculated results with the records of the ships.
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Hisayoshi TATANO, Tomokazu ODA, Norihiro MATSUMOTO, Shiro MATSUI, Masa ...
Article type: Article
Pages
19-27
Published: December 30, 1975
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This paper describes the results of an experimental study on rudder performance for large full ships. The following results of tests in three circulating water channels are discussed: 1) Results of rudder tests in an open water and those behind propeller. 2) The effects of aspect ratio of the rudder, propeller slip ratio and the propeller diameter to rudder height ratio. Two kinds of experimental formulas which give the normal force coefficient of rudder for large full ships will be proposed.
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Shoichi NAKAMURA, Ryusuke HOSODA, Shigeru NAITO, Morio INOUE
Article type: Article
Pages
29-39
Published: December 30, 1975
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With a ship model of single screw high speed container ship, resistance and self-propulsion tests in irregular head waves are carried out in the Experiment Tank of Osaka University. The significant wave height and the mean wave period of irregular waves are changed systematically. The significant amplitudes of heave, pitch and surge, and the mean increases of resistance, propeller thrust, torque and revolutions measured in irregular waves are compared with the values which are predicted from the response amplitude operators obtained by the experiments in regular waves and the wave spectra by applying the linear superposition method. The self-propulsion factors in irregular waves are analysed by the thrust identity method. To investigate the characteristics of self-propulsion factors in waves, the inflow velocity at the propeller disc in regular waves are measured by using a ring type wake meter, and the wake fraction, relative rotative efficiency and propeller open efficiency in regular waves are calculated by using the measured inflow velocity and propeller revolutions, and the propeller open characteristics based on the blade element theory.
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Shoichi NAKAMURA, Shigeru NAITO, Ryuichi INOUE
Article type: Article
Pages
41-55
Published: December 30, 1975
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In order to investigate the propeller characteristics in waves, open-water tests at the conditions of forced heave, pitch and surge oscillations in still water as well as in regular and irregular waves are carried out with a five bladed 15 cm diameter propeller. The mean values of fluctuation of the measured thrust and torque are compared with the open-water characteristics in uniform flow. Furthermore, self-propulsion tests in regular and irregular waves are carried out with a ship model of single screw high speed container ship, and propeller load fluctuations are measured. The measured amplitudes of propeller load fluctuation in open-water tests and self-propulsion tests are compared with the theoretical calculations by using the propeller open-water characteristics in uniform flow or the Sears' unsteady airfoil theory.
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Tetsuo TAKAHEI, Tetsuo TAGORI, Osamu KISHIMOTO
Article type: Article
Pages
57-63
Published: December 30, 1975
Released on J-STAGE: March 30, 2018
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During a recent decade in Japan, more than 20 circulating water channels have been constructed. The Circulating water Channel Group (CCG) was organized in 1966 and has been studying the improvement of the performance of the channel itself as well as the development of diversified test techniques. In 1971, the CCG decided to perform a co-operative resistance test of the standard model for the purpose of ascertaining the accuracy of the tank tests at sizes 2.O and l.5 meters in model length. This group has been devoted to this work for three years now. The results of resistance test are more individual among the water channels than among the towing tanks. Two important factors affecting the test results clarified through our study are the gradient of the free surface and the steady wave accompanied by the flow particularly in high speed range. The remedies for these factors lead the discrepancy of the test results to a fairly good agreement.
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Yoji HIMENO, Ichiro TANAKA
Article type: Article
Pages
65-73
Published: December 30, 1975
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Recently, several methods for predicting the development of the three-dimensional turbulent boundary layers around ship hulls have been established. Concerning the cross flow angle in the boundary layer near the stern, however, the question seems still to remain about which method is better for predicting the cross flow angle distribution. In this paper, the authors propose a new exact integral method for solving the boundary layer equation, which consists of some modifications to the authors' previous method and the numerical transformation of the streamline coordinates into the other coordinates defined by a n-parameter mapping function. The result of the calculation applied to ship forms shows that the downward cross flow appears near the stern and the scale effect of the cross flow angle cannot be neglected.
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Masatoshi BESSHO
Article type: Article
Pages
75-84
Published: December 30, 1975
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If we neglect the effect of viscosity as usual in the theory of water waves, the system of water motion would be conservative and the motion would be reversible. However, thus obtained time reversed motion breaks the radiation condition at infinity, so that such motion may not be physically realizable in general but some special cases. In this paper, the author represents the time-reversed velocity potential by the ordinary potentials which suffice with the radiation condition and incident regular wave and deals with its application in the theory of water waves. Also he deals with the relation between the reverse flow velocity potential and the time reversed flow one and gets the formula corresponding to the former case which enables us to estimate the effect of self-diffraction of waves in the wave-making resistance.
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Ichiro NAKAMURA, Taiji KATAZA, Masaru MOKUNAKA, Yoichi HATTORI, Hirosh ...
Article type: Article
Pages
85-94
Published: December 30, 1975
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In the first report authors presented an approximate calculation method of long-term distribution of random variables on the premise that their standard deviations are given. It was clarified that the expected values of long-term distribution were almost determined by the maximum values of the standard deviations and the corresponding average wave periods. In this report authors bring these two values into focus and their approximate calculation method will be presented. If the response functions are given, the maximum values of the standard deviations and the corresponding average wave periods can easily be obtained by this method.
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Ko NISHIMAKI, Tooru HORI, Masako TANAKA
Article type: Article
Pages
95-102
Published: December 30, 1975
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In the near future, various huge off-shore structures will be constructed. Concrete shall become a leading material in the structures, owing to its versatile properties. One of the limitations of concrete is its low tensile strength. The problem of low tensile strength of concrete is dealt with in main by two different methods: by applying prestressing and by designing the structural configuration so that no tensile stresses appear. In the paper, the authors discuss the application of partially spherical shell to huge off-shore structures. Structural analysis by using the finite element method were done in order to investigate the feasibility of the structure. The results were arranged as to certain parameters to derive design charts by which the stresses of check points can be presumed. Optimum shape is also discussed.
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Hisashi YAMAMOTO, Michi OHTA, Kuniharu FUKUDA, Takao YAMAMOTO
Article type: Article
Pages
103-110
Published: December 30, 1975
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In the case where HAT WALL is used for the deck panels, it is necessary for designers to estimate the natural frequeucy of HAT WALL. However, we have had no studies on the vibration of HAT WALL up to the present. This paper presents the results of vibration tests for the deck construction model and dcscribes the method for ca1culation of natural frequencies of HAT WALL, which was derived based on the method for calculation of natural frequencies of stiffened f1at plate by Okuda and Arima, and the way for calculation of coupled frequencies by Kumai. As the results, we recognized the following matters. (1) In the case of neglecting the effect of coupled vibration, the calculated natural frequencies are comparatively higher than the measured ones. (2) The estimation of coupled frequencies of HAT WALL can be made with good accuracy by the empirical coefficient defined in this paper.
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[in Japanese]
Article type: Article
Pages
111-115
Published: December 30, 1975
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Article type: Appendix
Pages
117-118
Published: December 30, 1975
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Article type: Appendix
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App2-
Published: December 30, 1975
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Article type: Appendix
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App3-
Published: December 30, 1975
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Article type: Cover
Pages
Cover3-
Published: December 30, 1975
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