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Article type: Cover
Pages
Cover1-
Published: September 25, 1989
Released on J-STAGE: April 01, 2018
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Article type: Index
Pages
Toc1-
Published: September 25, 1989
Released on J-STAGE: April 01, 2018
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Article type: Index
Pages
Toc2-
Published: September 25, 1989
Released on J-STAGE: April 01, 2018
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Kazuhiko HASEGEWA, Mato HATTORI, Takuji UEMURA, Tomoyoshi TANABE
Article type: Article
Pages
1-9
Published: September 25, 1989
Released on J-STAGE: April 01, 2018
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A methodology how to deal with pictures or to perceive their interference in computer systems is discussed. The proposed method can recognize not only various situations between two pictures, but also more spatial information between them. These functions to manipulate pictures are useful for some applications such as an intelligent CAD system and any computer systems in which pictures must be handled or perceived. The method is applied to an automatic layout design tool named Expert System for Shipboard Equipment Layout (ESSEL)
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Hiroshi ANDO, Sumio HAMAHIRA, Yasumitu TAKAGI, Kiyofumi NAGAO
Article type: Article
Pages
11-18
Published: September 25, 1989
Released on J-STAGE: April 01, 2018
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Ship outfitting department of Kawasaki Heavy Industries, LTD. has employed the Integrated CAD/CAM system for Hull and Piping. To achieve the total computerized system for shipbuilding, the authors have developed the entegrated CAD/CAM system for the electrical outfitting which is applicable to a wide range from the design stage to cable installation, by combining the CADAM (Computer- graphics Augmented Design And Manufactureing) system and KHI's own application system.
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Tsutomu HORI
Article type: Article
Pages
19-43
Published: September 25, 1989
Released on J-STAGE: April 01, 2018
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In this paper, a new transverse cut method in the type of Fourier transform is proposed on the field of wave pattern analysis. If this new method is applied for the analysis of asymmetrical ship waves, the amplitude functions of free wave is able to determine by use of only a sheet of transverse wave profile. That is to say, the amplitude function of elementary waves propagated toward the opposite side of each measured side are obtained in asymmetrical wavy flow field, when we transform a sheet of wave profile measured along the transverse cut perpendicular to ship's cource from centre line to infinity sideways both port and starboad sides by means of Fourier integral. The present methed of asymmetrical wave pattern analysis is applied to theoretical wave pattern generated by a submerged point doublet with oblique axis in order to confirm the reasonableness of present method. The effects of radiation condition of ship waves on the equation of wave pattern analysis are also mathematically studied in the case that the longitudinal position of transverse cut goes to infinity rearwards. Furthermore, the relationship between the newly proposed method and the ordinary method is theoretically showed on the transverse cutting wave pattern analysis in the form of Fourier transform and is numerically illustrated on the base of analysis for theoretical wave pattern generated by a submerged point source.
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Huai-Xin CHANG, Yoji HIMENO
Article type: Article
Pages
45-56
Published: September 25, 1989
Released on J-STAGE: April 01, 2018
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A numerical computation is made for an unsteady incompressible viscous flow around an oscillating body. The computationl method satisfies the continuity equation as well as the momentum equations in each time step, and can be featured by the terms lide finite difference, the third order upwind scheme, Euler implicit in time difference, iteration in each time step, etc. Using the present method, the viscous flow around a pitching elliptic cylinder is computed. It is found that the motion of vorticies around afterbody is cyclical in pitching motion, and the calculated values of the time-mean velocity variations from the steady-state values are of similar tendency to existing experimental results of the wake of ship form body.
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Naoki TANABE, Yoji HIMENO
Article type: Article
Pages
57-66
Published: September 25, 1989
Released on J-STAGE: April 01, 2018
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Present paper deals with a comparison of different numerical solution schemes for two-dimensional incompressible Navier-Stokes equation. Four MAC-type schemes are examined in view of the points whether Poisson equation for pressure is solved directly or not, and whether computational mesh is regular or staggered. A scheme from SIMPLE method is also studied in order to compare with the MAC-type schemes. A square cavity flow is adopted for the comparisons on the numerical stability, the convergence history, the continuity requirement both in a cell and in the whole region, and the results. It is found that the method of solving the Poisson-type pressure equation does not ensure the continuity requirement and that the regular mesh is not adequate for stabilizing the pressure term.
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Taketoshi OKUNO, Norio TANAKA, Yuji HASEGAWA
Article type: Article
Pages
67-74
Published: September 25, 1989
Released on J-STAGE: April 01, 2018
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In this research, the flow field measurement around ship hull at incidence was made by using five hole Pitot Tube which was operated by automatic flow measuring system. At first, the paper describes the developed system for flow measurements in circulating water channel. The system is consist of two parts: the sensor controlling system, a kind of a robot manupulator, and the data acquisition system. The system enables measuring of flow velocity vector around ship model automatically using several microcomputers which are cominucated through RS232C channel. The results of flow field measurment around ship hull at incidence are shown, at whole of the back side region from fore to aft peak. The vortex separeted at fore part travels with the outer potntial flow. Therefore, the path line of the vortex is different from that of full ship as a tanker model.
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Toshio SUZUKI, Takashi SHIRASE
Article type: Article
Pages
75-79
Published: September 25, 1989
Released on J-STAGE: April 01, 2018
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Tracer pathline images of flow field give us a great deal of information about the field and several methods were developed to obtain the velocity vectors from these pictures. In this paper, a new technique is proposed in order to obtain the velocity vectors from the picture of flow fields. The picture which contains long-time exposed tracer images is treated as an unintentional movement of a camera in taking the picture and the restoring method which makes multi-time exposed picture clear is introduced. A flow pattern is analysed and the results show that the technique is simple and useful to analyse the pathline images.
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Eiichi NISHIKAWA, Makoto UCHIDA, Noboru NAKAI, Hideo KAMIYAMA, Tetsuya ...
Article type: Article
Pages
81-88
Published: September 25, 1989
Released on J-STAGE: April 01, 2018
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The fluctuating pressure on the hull surface just above the propeller was measured and at the same time, the behavior of propeller cavitation observed by the case of the training ship "FUKAE MARU" of Kobe Mercantile Marine University. She has a overall length of 50 meters, a displacement of 784 tonnes, and a CPP with a diameter of 2.1 meters, with skewed angle of 40 degrees and with anti-clockwise revolution viewing from stern. Two pressure sensors were embedded in the hull surface so as not to disturbe the flow. The underwater video camera and the underwater strobe light were mounted on the port side hull near stern. Measurement trials were carried out over the certain ranges of blade angle and propeller revolution number. The trials made clear the followings, (1) as the propeller load increases, the pressure fluctuation increases and the cavitation developes further, (2) the increase of the pressure fluctuation becomes very rapid and the very sharp peak appears in the fluctuating wave when the cavitation occurs, (3) in the case of turning run, the fluctuating pressure is not so large as that of the straight run, and, when the turning direction is opposite to the direction of the propeller revolution, high frequency components appear distinctively.
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Masashi KASHIWAGI
Article type: Article
Pages
89-101
Published: September 25, 1989
Released on J-STAGE: April 01, 2018
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A 3-D integral-equation method is developed for predicting the hydrodynamic forces acting on and resulting motions of a ship, with the effects of tank-wall interference included. The proposed calculation method is restricted to the zero-speed problem, but provides in principle an exact solution for a body of arbitrary geometry. The integral equations for the radiation and diffraction velocity potentials on the body surface are derived by applying Green's theorem, and solved numerically with a discretization of the body in panels, with the velocity potential assumed constant on each panel. The Green function satisfying the tank-wall boundary condition is provided by first considering an infinite number of mirror images and then obtaining a closed-form expression for the resultant infinite series. Computed added mass, damping coefficient, and wave-exciting force for a hemisphere and for a ship with two planes of symmetry are compared with corresponding experiments which are also carried out in the present study. Virtually perfect agreement exists between experiments and numerical predictions, suggesting the validity of the present integral-equation method. Based on these reliable numerical computations, the characteristics of ship motions in a resticted waterway are studied
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Shigeru NAITO, Shougo OSHIMA, Shoichi NAKAMURA
Article type: Article
Pages
103-112
Published: September 25, 1989
Released on J-STAGE: April 01, 2018
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A complex offshore structure like a semi-submersible rig is disassembled into main floating bodies and simple component materials. The former usually are connected by the later. It is not always necessarily that the coupling materials rigid. In case of rigid connection, it is to consider the spring constant as approaching infinity. If we could know the behaviors of the multi-floating body system coupled with springs, the behaviors of it under every condition not only rigid but also soft connection could be known. When it is soft connection, each body moves relatively. There must be the unique condition like that whereas the main floating body does not move, small bodies around it move. It is important to know the unique condition for the main body, because not moving is better for her. It is interesting to make clear the mutual relation among the arrangement of floating bodies, dimensions of it, values of the spring constant and the sway motion. For predicting the variance of relative sway motion, it needs to know the sway frequency response function or floating bodies. The sway frequency response function can not be defined exactly in nonlinear system but under the restricted condition it could be defined, and it is useful. One interpretation of it is shown. The spectrum of the coupling forces among floating bodies is derived and the variance of the coupling stress is obtained to study the fatigue strength. The comparison results between experiments and calculations on sway motions, and coupling forces are shown.
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Akinori YUMURO
Article type: Article
Pages
113-121
Published: September 25, 1989
Released on J-STAGE: April 01, 2018
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This report deals with an approximate calculation of hydrodynamic forces generated by interactions between two ships which are moving along parallel courses at the same velocity, and hydrodynamic interactions of ships with a bank wall are also examined. With the assumption of the rigid free-surface and infinite water depth, the calculation method is based on the linearized thin-wing theory, using sources distributed over the center plane to represent thickness effects of two ship's bodies. A correction factor for equivalent distance between a ship and a bank wall is introduced to modify the ship breadth effect on the interaction forces, and the value of factor is determined experimentally From the present study, it is clarified that the correction factor is almost constant regardless of ship breadth and the separation distance. When adopting the modification mentioned above, this prediction method gives good qualitative agreement with experimental results for the interaction forces between two tanker-class ships.
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Kouichi SHOUJI, Tsuyoshi ISHIGURO
Article type: Article
Pages
123-132
Published: September 25, 1989
Released on J-STAGE: April 01, 2018
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The demands for the estimation of the ship maneuvering performance are increasing in the design stage with the computer simulations. Especially it is very important to evaluate the safety of the navigation in harbor because some skilfull ship operations such as short turning, parallel shifting, course keeping and so forth are carried out in restricted area. The hydrodynamic forces acting on the hull are small because the ship speed is slow in the harbor waterways. But the rudder force and the propeller force vary with the propeller load, and they become dominant for the maneuvering motion under the high propeller load condition. Therefore it is necessary to estimate precisely the rudder force and the propeller force under the various propeller load conditions. In this paper, some mathematical models are presented to evaluate the rudder force and the self-propulsion factors such as thrust deduction and wake under widely changing the propeller load condition due to the maneuvering motion in harbor. Some computer simulations about the short turning with engine and steering operation are carried out with above mathematical models. And these results show a good agreement with the experimental results.
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Keiichi KARASUNO, Kunisaburo YONETA
Article type: Article
Pages
133-143
Published: September 25, 1989
Released on J-STAGE: April 01, 2018
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Studies about wind forces acting on a ship's structures above the surface of water have been conducted by many researchers from old time, This is because wind forces cause speed loss and leeway of a ship in her navigation, difficulties in keeping her course and berthing performance during harbor maneuvering, swing motion and cutting of hawsers in her mooring, and so on. These wind forces have been analysed as a resultant force or components of longitudinal force X, lateral force Y and yaw-moment N. There is no research, however, which deals with these forces as described by a mathematical model like hydrodynamic forces during a ship's maneuvering, or composed of fluid dynamic components due to its characteristics, for example friction force, lift force and so on. This paper separates fluid force from ideal fluid force (Munk moment), lift and induced drag forces due to viscosity, and cross flow drag force. In particular, the cross flow drag coefficient C_D is assumed to be C_<D90> ∣sinβ∣ varing with drift angleβ (as mentioned in author's paper [1]) and the lift coefficient C_L is assumed to be proportional to cosβ multiplied by a coefficient which corrects for the small drift angle. As the result, longitudinal force X, lateral force Y and yaw moment N of wind forces acting on a ship are described by the following mathematical model X=X<uvv>v^2・cosβ+X_<uuuvv>(1/U)・uv^2・cos^2β+X_<u∣u∣>u∣u∣+X_<∣vv∣>・∣v∣^2 Y=Y_<uuv>・cosβ+Y_uuvvv(1/U)・v^3・cos^2β+1/2ρ∫C_<D90>∣sinβ∣・v・∣v∣・d_m・dx N=(m_x-m_y)uv+N_<uuv>・uv・cosβ+N_<uuvvv>(1/U)・v^3・cos^2β+1/2ρ∫C_<D90>∣sinβ∣・v・∣v∣・x・d_m・dx where u: Ucosβ, v: -Usinβ U: wind speed, β: wind direnction angle m_x, m_y: added mass, C_<D90>: cross flow drag coefficient atβ=90deg As a result of analysing wind forces acting on a 1/200 scale image model of a fishing boat measured by a wind tunnel test, it is indicated that the mathematical model mentioned above is very effective to describe wind forces X, Y and N and each of these forces can be subdivided into elementary components of fluid dynamic characteristics.
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Reiji YAMASAKI, Hiroaki KOBAYASHI, Yuji NAKANISHI, Hiroshi AINE, Kazuy ...
Article type: Article
Pages
145-153
Published: September 25, 1989
Released on J-STAGE: April 01, 2018
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This report deals with the maneuverability of a ship with stern bulb (SB), comparing with the conventional inverted G type stern (IG). From the results of model free running tests and full scale sea trials conducted for two 60,000 DWT tankers which have almost the same principal particulars except stern shape. i.e. SB and IG, the maneuvering characteristics of SB is compared with one of IG. Circular motion tests for two ships are also conducted in order to investigate the cause which makes maneuverability of two ships different, by analyzing the hydrodynamic derivatives obtained from tests. As a result, the following conclusions are obtaind. (1) The course stability of SB is less than that of IG on fully loaded condition. (2) The difference of hydrodynamic derivatives of naked hull between two ships causes the less course stability of SB (3) The intensity of bilge vortex in straight running seems to play an important role on characteristics of hydrodynamic derivatives. (4) Judging from comparison of two tankers, the difference of frame line of two aft bodies is more important on course stability than that of stern profile.
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Masami HAMAMOTO, Masaru SUEMORI, Keinosuke HONDA
Article type: Article
Pages
155-163
Published: September 25, 1989
Released on J-STAGE: April 01, 2018
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Some experiments of a stopping maneuver are carried out for a ship at seas. The items related to motions of the ship during stopping maneuvers have been measured in order to investigate the influence of initial speeds and initial conditons on head reach, lateral transfer, ship tracks and stopping time. The analysis of ship stopping is performed by using the simplified equation of motion in a straight course and the set of the three equations with respect to forward, sway and yaw motions. Finally the ship trajectories during stopping maneuvers are predicted for several initial speeds and several initial conditions and the predictions are compared with the experimental results. Althought the initial conditons are sensitive for the trajectories of ship during stopping maneuvers, the preditons seem to be fairly good agreement with the experimental results.
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Mitsuo YAMAMOTO, Ryozo TAKAHASHI, Shinjirou HAYASHI, Kiyoshi MATSUMOTO ...
Article type: Article
Pages
165-167
Published: September 25, 1989
Released on J-STAGE: April 01, 2018
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"Yokosuka" is equipped with underwater acoustic systems for measuring the Submergible position and communicating with the Submergible. Therefore maximum permissible noise level of "Yokosuka" radiation acoustic noise was set at the planning stage. We estimated the radiation acoustic noise level and applied noise reduction technique to main engines, many pumps and ship structures to build a low noise ship. On "Yokosuka" sea trial, we were certain that the radiation acoustic noise level was lower than the maximum permissible level and there was no bad noise source for underwater acoustic systems. This paper presents the result of underwater acoustic intensity on "Yokosuka" sea trial.
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Kohei MATSUMOTO, Hideyuki SYURI
Article type: Article
Pages
169-180
Published: September 25, 1989
Released on J-STAGE: April 01, 2018
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This paper presents newly developed database system of ship hull vibration and its application. By using statistical analysis programs of this system, empirical formulas can be generated successfully from experimental data-base. Some empirical formula concerning ship's rigidity for vibration analysis, 2-node vertical and horizontal natural frequency, damping factor and added mass were derived from this data-base, Well-known existing formulas were reviewed and compared with those obtained by this study. These results will give ship designers useful information. Moreover, future design method for vibration were discussed. This type of data-base will play an important role in vibration design of ship.
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[in Japanese]
Article type: Article
Pages
181-195
Published: September 25, 1989
Released on J-STAGE: April 01, 2018
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
Article type: Article
Pages
197-207
Published: September 25, 1989
Released on J-STAGE: April 01, 2018
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Article type: Appendix
Pages
App1-
Published: September 25, 1989
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Article type: Cover
Pages
Cover2-
Published: September 25, 1989
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