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発行日: 1995/03/25
公開日: 2018/04/01
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発行日: 1995/03/25
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原稿種別: 目次
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発行日: 1995/03/25
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原稿種別: 目次
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発行日: 1995/03/25
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山野 惟夫, 山下 保己, 岩崎 泰典, 田口 和典
原稿種別: Article
p.
1-12
発行日: 1995/03/25
公開日: 2018/04/01
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Rotational flows exist in the propeller slip stream in any ships. If any method is developed that can recover the rotational flows (energy loss) efficiently, it will surely contribute to the energy saving of ships. The authors have made efforts to develop a practical apparatus for this purpose and finally developed Kawasaki RBS-F (Kawasaki Rudder Bulb System with Fins, called "RBS-F" hereinafter, patented). To date, RBS-F has been installed on more than 40 ships, mostly large full ships, because of its practical characteristics. This paper describes the development of RBS-F and its application to full scale ships.
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別所 正利, 佐久間 俊
原稿種別: Article
p.
13-20
発行日: 1995/03/25
公開日: 2018/04/01
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When a high-speed displacement ship is designed, it is the most interesting thing for designers to reduce her residual resistance, because it takes the large part of her total resistance. According to recent studies, it is known that the residual resistance consists of wave-making resistance, spray resistance and water head resistance. It is hence necessary to study how to reduce each resistance component. It is possible theoretically to make a hull form whose all components are minimized, however, the obtained hull form is hard to be realized. The study how to realize is carried out, then a practical form which has small spray at the bow is obtained. However, the form does not give small wave making resistance though it is possible theoretically to reduce wave making resistance. In this report, it is discussed how wave making resistance is reduced on the spray free condition. The result shows that diminishing bow spray and reducing wave making resistance are affected each other, and it is hence impossible to reduce both of them at the same time.
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村上 光功, 姫野 洋司
原稿種別: 本文
p.
21-27
発行日: 1995/03/25
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One of the most important things for designing a structure of bluff shape in unsteady current, is to predict in advance the unsteady forces due both to the unsteady flow and to its oscillating motions. But, it seems that there has been no practically reliable methods of predicting the flow and forces around such an oscillating bluff body even in 2-dimensional case. On this point of view, the authors have recently developed a new Vortex-Shedding Panel Method suitable for both lifting and non-lifting problem for an arbitrary 2-dimensional section in steady flow. The un-knowns are source and vortex densities distributed on the body surface, in which the surface boundary conditions are specified both outside and inside the surface. This leads to a well-posed problem in mathematical sense, forming a Fredholm type integral equation of the 2nd kind, and ensures steady convergence in numerical computation, differing from usual discretization methods. In this paper, a general unsteady problem for oscilating bluff section under unsteady incoming flow is studied and numerical examples are also shown for the case of oscillating rectangular cylinders in uniform flow. The results of it show quite good agreements with experimental data in aspects of the hydrodynamic oscillating forces and the pressure distribution on the body surface.
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濱崎 準一, 姫野 洋司
原稿種別: 本文
p.
29-34
発行日: 1995/03/25
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This paper describes an attempt of improving ship prismatic form. i.e., longitudinal displacement distribution, for minimizing ship wave resistance. The method adopted here represents the prismatic curve by use of B-spline function, takes the coefficients of the B-spline as the design variables, and evaluates the wave resistance value by Michell approximation which assumes an infinite-draft ship form with the beam profile same to the prismatic curve of the ship form considered. Then a feasible direction method is applied to the optimizing process including the above procedure of wave resistance computation. It is found that the convergence of the iterative optimizing process is quite rapid and steady, and that the method is useful for practical initial design of ship forms, although it also leaves some aspects of improvement such as wave resistance calculation method and extention to 3-dimensional case.
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岡本 幸彦
原稿種別: 本文
p.
35-42
発行日: 1995/03/25
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This paper deals with the influences of skew back of propeller and wake distributions on hull pressure fluctuations caused by cavitating propellers. At first, three model propellers with different skew angles were tested in the cavitation tunnel in the same model wake distribution. The extent of cavity, the cavity thickness distributions and the pressure fluctuation on the flat plate above the propeller were measured and compared with the unsteady lifting surface theory. Secondly, the influence of the scale effect of wake distributions on the propeller cavtation and the hull pressure fluctuation were investigated by the same calculation method comparing the full scale and model scale data of Seiun-Maru. The results of the experiments showed the increase in the cavity thickness near the propeller tip passing through the high wake region as the increase of skew angle. The calculations estimated thicker cavity thickness near mid span region and thinner cavity thickness near tip region than the experiments. But the thicker cavity thickness due to the skew back could not be simulated by the calculations. The pressure amplitudes of the full scale ship could reasonably be estimated taking the scale effect of wake distributions into account, execpt for the case of highly skewed propeller.
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池田 良穂, 片山 徹, 山下 保己, 大塚 耕司, 前田 孝雄
原稿種別: 本文
p.
43-48
発行日: 1995/03/25
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An experimental system to measure hydrodynamic forces acting on models of high speed planing craft is developed for a medium sized towing tank of length 70m. The light towing carriage towed by two wire can run up to a speed of 15m/s. The measured forces acting on two fixed models towed by the system are in fairly good agreement with that from the same models by a conventional towing carriage. A simulation of the attitude and resistance of a craft using the database of hydrodynamic forces measured by the system is also carried out and is compared with the result of conventional resistance tests. The comparison shows that the simulation result of the running attitude is in fairly good agreement with the experimental result. The reasons for the deviation of the resistance is explained in this paper.
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田中 一朗, 馬 坤
原稿種別: 本文
p.
49-57
発行日: 1995/03/25
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This paper describes a method for obtaining the optimum ship form of low resistance and high propulsive efficiency including experimental validation. The authors presented two papers before regarding a method for obtaining the optimum ship form of low resistance with consideration of separation prediction. In the present paper a method for considering propulsive efficiency starting from the lowest resistance form is described. The method is applied to the Series 60 model of 0.60 Cb. Resistance and self-propulsive efficiencies of two optimum models produced with different constraints are measured at the circulating water tank. The results of experiments show effectiveness of the present method for obtaining ship form of low resistance and high propulsive efficiency.
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平山 次清, 宮川 清, 高山 武彦, 佐竹 秀紀
原稿種別: 本文
p.
59-66
発行日: 1995/03/25
公開日: 2018/04/01
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For the safety of ocean going sailing yacht, not only intact satability but also restoring characteristic from capsizing is very important. Sudden capsizing from upright condition occurs in a direct hit by a plunging breaker higher than the ship breadth. This time we report about the restoration of a 47 feets sailing yacht in two dimensional plunging breakers and capsizing in newly developed multi directional concentrating and breaking Transient Water Waves. We call this wave as Isolated Triangular Transient Water Waves (ITTW).
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湯室 彰規
原稿種別: 本文
p.
67-73
発行日: 1995/03/25
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Assuming that a ship's hull can be replaced by a rectangular flat wing, a simplified method is examined for calculating the hydrodynamic forces and shedding angles of the trailing vortices in shallow water. This method is based on the INOUE's method developed by applying the nonlinear lifting surface theory. The integral equation, which determines the vorticity distribution and the shedding angle, is solved under the condition of finite water depth. In order to obtain better agreement between observed and calculated values, some discussions are made for improvement of the prediction procedure. A comparison is made between the shedding angles evaluated using induced velocities on wing surface and at the location of trailing vortex. And these calculated values are compared with experimental results. Furthermore, it is indicated that to take account of the retained circulation effect is essential for predicting the hydrodynamic forces in shallow water. By adopting the measured values as the shedding angles, calculation of the hydrodynamic forces is made changing values of the retained coefficient which is defined as the ratio of vorticity at the tip to uniform spanwise vorticity. As a result, it is confirmed that there is a tendency for values of the coefficient to increase with decrement of water depth.
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清水 信行, 永海 義博, 鹿取 正信, 池田 良穂, 野本 謙作
原稿種別: 本文
p.
75-80
発行日: 1995/03/25
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Stability of a capsized ship depends not only on the location of its center of a gravity and hull form, but also on the subdivision and the weight of flooded water. In the present paper, to clarify the stability characteristics of a flooded and capsized ship, the authors developed a computer program to calculate the restoring force. The program is validated using the results of experiment done with the model of barge. A full scale experiment of a capsized yacht is carried out to observe its restoration process to upright condition and the speed of flooding. On the basis of the experimental results, some calculations of the stability quality of the capsized yacht are done by the computer program.
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小林 弘明, 新井 康夫, 石橋 篤, 奥田 成幸, 岡本 康裕, 竹内 昭文
原稿種別: 本文
p.
81-89
発行日: 1995/03/25
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Recently, small high-speed boats increased cause by popularization of marine leisure. But, their maneuvering characteristics are not studied enough, because of difficulty of measurement of ship's position and velocity. It is needed for estimation of ship motion to measure the ship's position and velocity continuously with high accuracy. New measuring system that use the δ rang (Doppler effect of the GPS signal) of Differential Global Positioning System is developed. The accuracy of position measured by this system is less 1.0m so that maneuverability of high speed boat can be estimated. In the paper, estimation methods of maneuvering characteristics are discussed through the test results of 3 kinds of high speed boat. In order to know the maneuverability of high speed boat, fundamental maneuvering motion test such as speed trial with an extensive variation in engine revolution, turning and zigzag motion test are carried out. The mathematical model eq. (6), (7) proposed by this paper are not only simple, but this model also express the maneuvering characteristics of small high speed boat with high accuracy.
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小林 弘明, 志村 雄一
原稿種別: 本文
p.
91-98
発行日: 1995/03/25
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Total mission of transportation is not completed without safe and reliable berthing. In order to evaluate the berthing maneuverability, total system including ship, characteristics of actuators and control system must be considered. The control system that require the maximum ability of ship characteristics including actuators is necessary. In this paper, at first, optimal controller that realize the required condition mentioned above, are developed. Proposed control system use the Joy-stick controller and fuzzy control theory, this system is easy to handle the ship pure sway motion for any direction such as pure transverse drifting that is often required at the berthing maneuver. Second step, berthing maneuverability is evaluated using proposed controller from view point of ship type, actuator type and its ability. Following results are obtained; ・The pure sway ability in forward direction depend on the bow thruster power, and ability in afterward depend on the rudder force. ・The pure sway motion using conventional actuators may be limited under wind disturbance, in order to realize the required ability, it is necessary to decide the actuator power based on ship characteristics and required condition.
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笹島 洋, 金山 維史
原稿種別: 本文
p.
99-104
発行日: 1995/03/25
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In analyzing the vibration of hull girder or tank wall in contact with fluid, the influence of virtual mass is one of the most important factors to increase the accuracy of analysis. Previous calculation method used the source or doublet respectively, however actual vibration of structure is frequently combined free edged plates with both side in water and tank walls with oneside in water. Then authers made the analyzing method with combined with source and doublet, and confirmed that this method is practically effective for the vibration of ship structure in fluid. This paper show these analyzing method and few calculation examples of ship structure vibration.
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斎藤 年正, 小川 義孝, 八尾 英男
原稿種別: 本文
p.
105-112
発行日: 1995/03/25
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Underwater explosions cause gas bubbles. If gas bubbles are generated at deep underwater, expansion and contractions are repeated as they float to the surface. Expansion and contraction in gas bubbles in turn cause flow in surrounding areas, thus inducing ship hull whipping at the proximity of gas bubbles. In extreme cases, the whipping may generate much longitudinal bending stress on the ship hull. For the structural design of ship hull which is to be subject to gas bubbles, it is necessary that quantitative analysis of whipping-caused longitudinal bending stress be performed for evaluating ship hull structural strength. This paper describes the vibration analysis method using a simple beam model for the ship hull structure in order to perform numerical analysis of whipping. It also discusses a calculation method for the kinetic characteristics of a fluid during expansion and contraction of gas bubbles which induce whipping. In addition, effects of gas bubbles on whipping are examined by calculation.
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笹島 洋, 水野 博介, 楠本 裕己, 金山 維史
原稿種別: 本文
p.
113-118
発行日: 1995/03/25
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It is known that vibrational characteristics of a ship are influenced by its loading conditions. To make clear the influence, we carried out vibration measurements onboard a container ship in service. Furthermore, we calculated their modes of vibration and modal parameters, by whole ship FEM to evaluate the measured data quantitatively. As the results, (1) we obtained vibration measurement results in 3 loading conditions. (2) we represented loading dependant variation in mode of vibration and natural frequency by FE analysis. (3) we identified modal parameters in 3 loading conditions by FE analysis in conjunction with measurements.
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修理 英幸, 北野 智子
原稿種別: 本文
p.
119-125
発行日: 1995/03/25
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The analysis method of the structure-borne sound on the steel or aluminum structure like a ship is examined at low frequencies. Statistical energy analysis (SEA) is a good way of predicting the spatially averaged velocities of structures at high frequencies. It is, however, not good for SEA to identify specific power flow paths through a structure or to estmate spatial variations of power flow in the substructures at low frequencies. In this paper, the finite element method (FEM) is used to calculate the vibrational power flow of simple plate models and an actual ship structure. MSC/NASTRAN, which is a widely used program for structural dynamics, is applied to calculate the velocities at grid points and the forces on elements of a structure. Then these NASTRAN output are transformed the vibrational power flow of a structure. First, the application of a FEM model to the power flow calculation is discussed. Both beam elements and plate elements are considered as structual elements. Next, a simple plate model is analyzed to verify the power flow distribution on a substructure and to predict the influence of the damping treatment upon the power flow. Finally, it is shown that this method can be applied to predicting the input power from a noise source like a main engine to the hull structure of a high speed ship.
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谷川 雅之, 摩嶋 禎規, 永濱 信一, 柴崎 公太
原稿種別: Article
p.
127-131
発行日: 1995/03/25
公開日: 2018/04/01
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The TGZ membrane system, which is one of the insulation systems used for the cubic tank type LNG carrier, is a layered structure of orthotropic materials and has a complex stress distribution owing to the discontinuities of geometry and material. Stress distributions obtained from 2-D FEM model usually employed in the structural design were compared with those from 3-D FEM model under typical load conditions. 2-D FEM model assuming plane strain condition was found to be mostly conservative and could be valid for design use.
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上田 幸雄, 岡田 博雄, 正岡 孝治
原稿種別: 本文
p.
133-138
発行日: 1995/03/25
公開日: 2018/04/01
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This paper proposes an estimating method of buckling strength of rectangular plates subjected to combined in-plane loads. This method uses a few selected eigen-functions for lateral deflection and in-plane deformation and very accurate results can be obtained in short computation time, if appropriate eigen-functions are determined. The boundary conditions of rectangular plates are either simply supported or clamped along all edges. Using this method, buckling interaction curves are obtained, which are very accurate in comparison with the exact solutions. Through above numerical examples, it is demonstrated that this method is very practical to use at the design stage of ship structures.
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的場 正明, 熊本 啓行
原稿種別: 本文
p.
139-144
発行日: 1995/03/25
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Programme fatigue test is a one under the cyclic loading as a block which has a number of cycles of load with some kinds of amplitude of stress. This test is to acess fatigue strength of products under modified conditions near to actual load. Many kinds of block patterns are inevitably to be considered. On fatigue design of products, programme fatugue test under some block patterns are examined for the restriction of time and cost and a study on lifes for the other patterns is done with the application of Miner's rule, modified Miner's or Haibach's method. Unfortunately, the estimated lifes irrespective of the above methods are widely scattered in comparision with experiments. This paper describes a proposal of the dependence of block patterns on crack initiation life for programme fatigue.
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藤本 由紀夫, 新宅 英司, 宗 智, 石倉 功史, 磯上 哲弘
原稿種別: 本文
p.
145-152
発行日: 1995/03/25
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A probabilistic model for the determination of membership function based on fuzzy data is proposed. First, an experiment on the perception of triangle area by human is carried out in order to see the relationship between subjective value, у, and objective value, χ. It is found that the subjective value can be expressed by a probability density function f_Y(у), in which mean of f_Y(у) has a distance from χ and standard deviation of f_Y(у) is a function of χ. By introducing subjective classification boundaries, the process of subjective classification is expressed by a probabilistic model. In the model, membership grade, which is same as the probability that an objective data χ is classified into small, medium or large, can be calculated by the integration of f_Y(у) in the range between respective classification boundaries. Actual calculation of membership grade is carried out on objective coordinate. The f_Y(у) and the subjective classification boundaries are all mapped onto objective coordinate and a probability density function f_X(χ) and objective classification boundaries are newly introduced. Normal, beta and uniform distributions are assumed for f_X(χ). The mean of f_X(χ) is approximated by the objective value χ. The standard deviation of f_X(χ) and the objective classification boundaries are determined from the fuzzy data by the likelihood analysis. The proposed method is applied to the fuzzy data obtained by the experiments on the perception of triangle area. It is concluded the membership function can be determined for every type of f_X(χ). Further, it is found that the proposed method can generate triangle and trapezoid membership functions too.
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南部 森雄, 田中 太一, 村川 英一, 上田 幸雄
原稿種別: 本文
p.
153-159
発行日: 1995/03/25
公開日: 2018/04/01
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Monte calro simuration is one of the effective methods to estimate the failure probability of complex structures involving many mutually dependent failure modes. However, since this method requires a large number of structural analyses, it is desirable to develop a method to improve the computational efficiency. For this purpose, new type of importance sampling method in which a concept of equivalent failure surface is introduced is proposed. Its effectiveness is demonstrated through a simple example of truss structure.
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楠 剛, 京谷 正彦, 石田 紀久, 伊東 章雄, 落合 政昭
原稿種別: 本文
p.
161-167
発行日: 1995/03/25
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Nuclear powered ship, which has advantages of voyage capability with a high power level, are directly or indirectly influenced by ship motions or sea wave. Although the effect of ship motions or sea wave on the reactor system is important in designing or operation of marine reactor, the data obtained from the prototype marine reactor are not many in the open literature. Mutsu conducted the experimental voyage in order to obtain the data concerning the effect of ship motions and sea wave on the reactor system. The behavior of reactor system were analyzed by the data of wave height, ship motions and turbine load in the case of the experiments in ship maneuvering and straight cruising against swell. The response of reactor power and water levels in the steam generator and the pressurizer to the wave, ship motions or maneuvering were revealed in the present paper.
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馬場 信弘, 木村 直貴, 高松 健一郎
原稿種別: 本文
p.
169-174
発行日: 1995/03/25
公開日: 2018/04/01
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A numerical model of the mixing in stratified flows is developed based on the finite volume solution of the incompressible Navier-Stokes equation for a heterogeneous fluid, the continuity equation and the transport equation for solute. To incorporate the effects of small density difference on the flow field into the model with some degree of accuracy, the density variation relative to the characteristic density difference is used as one of primitive variables. The discretisation used holds the conservative property with respect to mass for the governing equations as well as the boundary conditions. The two-dimensional computation of mixing in a stratified cavity flow by a vertical circulation penetrating into the region of constant density gradient is carried out to validate the numerical model by comparing with the experiments in the previous paper. It is found that this model reproduces the deepening processes of a mixed layer in qualitative agreement with the visualization experiments in which a density interface formed by erosion of the basic density gradient suppresses the primary circulation to penetrate it. The effects of diffusivity of solute on the characteristics of the mixed layer and the stratified layer are investigated to estimate the mixing rate across the density interface.
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井上 実, 馬場 信弘, 平尾 和誉, 高松 健一郎
原稿種別: 本文
p.
175-179
発行日: 1995/03/25
公開日: 2018/04/01
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The formation of streamwise vortices in an unsteady viscous flow around an oscillating circular cylinder is investigated by numerical simulation based on the finite volume solution of the three-dimensional Navier-Stokes equations. The small disturbance given to the initial velocity field is amplified due to the instability of the oscillating flow to form the three-dimensional flow structure. In the formation process the streamwise vorticity component increases with its fluctuation with half the oscillation period. The development of the three-dimensional structure is much slower than that of the two-dimensional structure in the plane normal to the cylinder axis. It is found that on both sides of the cylinder the raws of pairs of the counter-rotating streamwise vortices place in alternating arrangement. The streamwise vortices are also formed along the center plane of the flow in front of and behind the cylinder, each of which has the opposite rotation of streamwise vortices on the sides of the cylinder at the same section. Tracing the vortex lines in the residual field suggests that these structures of streamwise vortices should be locally closed in the vicinity of the cylinder.
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船木 俊彦, 山本 次郎, 永田 良典
原稿種別: 本文
p.
181-188
発行日: 1995/03/25
公開日: 2018/04/01
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In case of calculating the motions of ships and offshore structures in waves, the structures had been assumed as rigid bodies. However, we can't exclude the effects of elastic deformations on the motions of large floting structures such as a floting airport at sea, because of relative smal bending rigidity and low natunal frequencies. In this paper, we examined the motions of two floating structures joined with leaf spring by experiment and modal synthesis analysis, considering the effects of the elastic deformations of these structures. The reason why we use modal sysnthesis analysis is that we have advantages of reducing degrees of freedoms. Therefore, we can calculate responses earliear by using modal sysnthesis analysis althrough the object of our study has large degrees of freedoms. Another most important advantage is that we can express rigid motions and elastic vibrations in parallel.
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原稿種別: 付録等
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App2-
発行日: 1995/03/25
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原稿種別: 表紙
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Cover2-
発行日: 1995/03/25
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