著者

金井 亮浩 宮田 秀明

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.1995, no.177, pp.147-159, 1995 (Released:2010-01-22)

参考文献数

16

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The free surface shock wave (FSSW) generated by a wedge model is numerically studied. The numerical simulations performed by the finite difference method employing density function method show the systematic variation of the shock phenomenon due to the Froude number based on the draft as obtained by experiments. The typical nonlinear phenomena like wave breaking and abrupt changes of velocity vectors are successfully captured and the details of wave breaking induced by the FSSW are clarified. Wave breaking occurs to weaken the nonlinearity and shear vortex and longitudinal vortex are generated from the overturning point on the free surface. After the wave breaking a steep wave is reproduced due to the nonlinearity. This seems to be periodically repeated.

著者

吉野,亥三郎

出版者

日本造船学会

雑誌

日本造船学会論文集

巻号頁・発行日

no.174, 1993-12

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Focussing on the sea-going maneuverability of a 105-passenger hovercraft, the authors made investigations through series of model tests and computer simulations. The wind forces acting on a scale model, which represents superstructure and cushion form, were measured in a wind tunnel test. Oblique towing tests with self-lifting model were carried out for the hydrodynamic characteristics between cushion skirt and water plane. Regarding the characteristics of control surfaces, the force measurement tests with ducted propeller and rudder in wind tunnel were carried out. Based on these results of model tests, the authors developed a simulation program which employs proper mathematical models for each force components, namely cushion skirt, wind, propellers, rudders and thruster. The output of simulation showed fairly good agreement with the results of actual sea trial. Especially in the case of course keeping in beam wind, the reverse of check-helm direction around Froude number of 1.0 experienced in actual operations were confirmed through computer simulation. Lastly the results of extensive investigations on the sea-going maneuverability of the hovercraft are explained.

著者

安川 宏紀

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.1999, no.186, pp.1-6, 1999 (Released:2009-09-04)

参考文献数

11

---

A hull form improvement method is presented using Genetic Algorithm in conjunction with Rankine source method based on a wave resistance theory for modified hull. By means of the present method, improvement of fore ship form is introduced for Series 60 (Cb =0.6) hull. As a result, the wave resistance is reduced about 25% at Fn=0.3 by modifying the original form to bulb-like bow shape. We found that GA improves the estimation accuracy of the optimum hull form.

著者

遠藤 倫正 横田 公男 森鼻 英征 渕上 勝人 広瀬 衞 下山 仁一

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.1980, no.148, pp.107-120, 1980 (Released:2009-09-04)

参考文献数

31

被引用文献数

1 1

---

The pressure hull of a deep submersible is a unique structure which requires sophisticated technology in its design and fabrication aspects. This paper presents the design and fabrication practices, which the authors have adopted to the pressure hull of the 2, 000m deep submergence research vehicle, “SHINKAI 2000”, ordered by Japan Marine Science and Technology Center. She is an up-to-date research submersible, having the greatest depth capability in Japan.She is under construction in Kobe Shipyard of MHI and scheduled to be completed in Oct. 1981. Her pressure hull has been tested successfully under external pressure of 1. 1 times as much as maximum operating depth. To complete the hull, the results and experiences from the R & D, which the authors have conducted extensively since 1969, have been effectively applied.This paper also discusses the future subjects to the deeper submersible, such as 6, 000m and deeper classes.

著者

金井 一彦 森鼻 英征 山崎 敏樹 寺田 邦夫

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.1972, no.132, pp.269-279, 1972 (Released:2010-01-22)

参考文献数

14

被引用文献数

1

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In order to obtain the collapse strength data on the spherical shells suitable to the pressure capsule of DSSV, collapsing tests were conducted using spherical shell models by means of MHI 1, 200 kg/cm2 hydrostatic tank. These models were made from several kinds of materials including ultra-high yield strength steels such as 18% Ni maraging steel, 10% Ni dual-strengthened steels etc., and machined into near-perfect spherical shape or spheres with initial imperfection of various, thicknesses.From these experiments the following conclusions are obtained : (1) Collapse pressure of relatively thick shells (ha/R10≥0.03) agrees to the theoretical inelastic buckling pressure by Gerard et al.(2) The effect of initial imperfections are evaluated by local radius in case of relatively thick shells. But for thinner shells, this method is not sufficient and nonlinear elasto-plastic analysis will be required.(3) Present results will not always agree with Krenzke's data, especially in thinner shells with flat spot.(4) Fracture appearance of collapsed shells are closely related to the fracture toughness of materials.

著者

土井 康明 茂里 一紘 堀田 多喜男

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.1991, no.170, pp.55-63, 1991 (Released:2009-09-04)

参考文献数

10

被引用文献数

1

---

A drag reduction for 3-dimensional body is attempted by microbubble injection. Two models with different lengths are used for experiments to distinguish the resistance due to on microbubble injection itself and the skin friction affected by microbubble covering. A reformed Wigley model is used to investigate the effect of microbubble injection on wave making. Measurements of the resistance and the longitudinal wave profiles are performed. The covering by microbubbles is realized by injected air through a porous pipe with pore size of 15 μm. The flow of microbubbles is obsered and the bubble sizes are estimated based on the rising velocity of a bubble in still water.The results show that it is possible to reduce the resistance of a 3-dimensional body by use of microbubbles if the body is well covered by microbubbles. Although the resistance increases where microbubbles are injected, the local frictional resistance is reduced more than 20 % where microbubbles cover the body. The total resistance is reduced more than 5 %. Based on a wave analysis, it is found that injecting microbubbles into water does not affect on wave making resistance.

著者

安川 宏紀 宮沢 多

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.2001, no.190, pp.181-190, 2001 (Released:2009-09-04)

参考文献数

4

被引用文献数

1

---

試験は, プロペラの回転方向として, 内回りと外回りの2つについて実施し比較した。試験結果をまとめると次の通りである。1. 内回りプロペラにおいては, 船尾が岸壁から離れ難く, 横移動が不能となる場合もある。外回りプロペラにおいては, 横力が明らかに大きいようであり, 船尾が岸壁から離れ易い。横移動が不能となることはない。2. プロペラ回転数の組み合わせをDS/S, S/Hと変化させても, 内回りプロペラ装備船の離岸性能の改善効果はほとんど見られない。同様に, 右舷舵角を0, ±35degと3種類変更させても, 離岸性能改善に大きな効果はない。3. 船の初期位置を岸壁からは離れたところに持ってくると, 横移動は容易となる。Fig.4に横移動試験結果の1例を示す。船影は10sec毎の右から左に動く模型船の位置を表している。内回りプロペラ (Inward) においては船がほとんど横に移動していないこと, 外回りプロペラ (Outward) においては所期の通り船尾が岸壁から離れた後で横方向へ移動していることが分かる。

著者

横尾 幸一 矢崎 敦生 伊藤 達郎 杉村 泰 門井 弘行 安部 光弘 吉野 信治 月野 良久 山崎 一夫

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.1973, no.133, pp.33-47, 1973 (Released:2010-01-22)

参考文献数

16

---

Recent extension of the container transport system has lead to the remarkable increase in both speed and size of container ships. Since there is a practical limitation to the maximum output of an individual engine, multiple-screw propulsion will become necessary for a large container ship to attain a higher speed with a large capacity of transport than the speed of 25 knots. Comprehensive research works have been conducted with the aim at developing a high speed container ship with triple-screw to be built at Mitsui Shipbuilding & Engineering Co., Ltd. in 1972, for the service between Europe and Japan.This report deals with comparative tests among single-, twin- and triple-screw propulsions, and with mutual interference between the hull and propellers, cavitation researches and full-scale measurements on the triple screw ship. Such other items of research works as vibratory forces of the propellers will be reported in a later paper.Principal conclusions obtained are as follows, 1) A triple-screw ship has a better propulsive performance than a twin-screw ship.2) For the triple-screw ship adopted, inward rotation of the wing propellers gives better propulsive efficiency than outward rotation, which is explained both by the wake measurements by 5 hole pitot tubes and by the results of the self-propulsion tests.3) Mutual interference between the center and wing propellers can be neglected practically.4) The effect of variation of the load of a propeller on the self-propulsion factors of each propeller will be negligible, unless the variation is too large.5) Added resistance of the appendages is also subject to the scale effect.6) Decreasing the camber of the propeller section near the leading edge was shown to be an effective means to decrease the amount of back cavitation, both on the ship and on the model.

著者

小池 裕二 佐伯 愛一郎 牟田口 勝生 今関 正典 宮部 宏彰 山下 誠也

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.1999, no.185, pp.111-117, 1999 (Released:2009-09-04)

参考文献数

6

被引用文献数

2

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An actively controlled anti-rolling system has been developed with a view of reducing the rolling motion of ship. It is a new type of anti-rolling systems to replace the conventional systems, such as anti-rolling tank and fin stabilizer, and is of hybrid type combining the pendulum-base passive type with active type driven by relatively small electric motors. This system is composed of a moving weight oscillating on rail shaped in circular arc, carrying the driving motors and reduction gears, and the passive, compact mechanism is realized. The driving force to control the movement of the moving weight is imparted from the electric motors through reduction gears connected to a lack and pinion mechanism. The actual system of a moving weight of 100 tons has been applied to oceanographic research vessel “MIRAI” (8672 GT.) for practical use. Prior to service at open sea areas, the control system has been designed based on the identified parameters of ship motion characteristics obtained by results of forced rolling oscillation test using anti-rolling system in the calm sea. Control performance and dynamic behavior have been analyzed by recorded data of ship motion and displacement of moving weight at open sea areas. It has been revealed that the system operated following the control law and provided performance to be aimed in design.

著者

金綱 正夫 関本 恒浩 関田 欣治 島田 潔

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.1994, no.175, pp.227-239, 1994 (Released:2009-01-08)

参考文献数

18

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This paper deals with the measured data obtained through the at-sea measurement of the TLP “EHIME”, an offshore nursery pilot firm station of Marino-Forum 21, of which tendons are parallel wire strands (PWS) protected by polyethylen sheath with specially manufactured cushion rubber rings at each ends and connected to a gravity type template through a belimouth shape structure. The measured data of the TLP dynamic responses are compared with theoretical estimation, and the strength performance of PWS as TLP tendons are discussed.The main results are as follows; 1) the TLP with the PWS mooring system has the same dynamic response characteristics as the conventional TLP with the steel pipe mooring system, 2) the mooring system by use of PWS type tendons adopted for the TLP “EHIME” exhibits sufficient strength and durability characteristics.

著者

徳永 純一郎 延永 尚志 中谷 龍男 岩崎 徹 福田 和廣 國武 吉邦

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.1998, no.183, pp.45-52, 1998 (Released:2009-09-16)

参考文献数

7

被引用文献数

1 3

---

This paper proposes a new concept for the frictional drag reduction technique. The new technique makes use of a specific coating surface (Super-Water-Repellent Surface) which has a highly repellent effect and an ability to form a thin air film over it under water. When supplying a small amount of air to the specific coating surface from the outside continuously, the supplied air (secondary air) is absorbed in and joined with the primary air film and spread to form a filmy air flow along the surface. This technique reduces the frictional drag because of this phenomenon.A frictional drag test in the rectangular pipe flow and a resistance test of horizontal flat plate were carried out in order to verify the validity of this technique. As a result of these tests, it was confirmed that drag reductions of about 80% and about 55% were obtained for flow velocities of 4 m/s and 8 m/ s, respectively.

著者

藤野 正隆

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.1968, no.124, pp.51-72, 1968-12-20 (Released:2010-01-22)

参考文献数

10

被引用文献数

3 3

---

前節で述べたように実験周波数には上限と下限があるが, さらに各状態での実験結果を比較するには特定のω'についての結果を用いることにした。そのためマリナー型船についてはω'=0.22~0.26, 東京丸についてはω'=0.17~0.20の結果を選んで以下の解析に使用した。

著者

新谷 厚

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.1985, no.158, pp.33-39, 1985 (Released:2009-09-04)

参考文献数

8

被引用文献数

1

---

In this report, we deal with statistical analysis for resistance of high speed ship forms in still water.Ship forms are classified into two types, i. e. naked hull with bow dome and without bow dome.Multiple regression equations for residual resistance are obtained by regression analysis on results of resistance test. And also, multiple regression equations for wetted surface area are obtained.Using these formulae, it will be able to estimate easily effective horse power over a wide range of speed.Estimation formulae are very available when designed, and in the future there is a possibility of finding the direction to improve ship forms.

著者

永井 保 吉田 靖 樋口 道之助 近藤 潔

出版者

公益社団法人日本船舶海洋工学会

雑誌

日本造船学会論文集 (ISSN:05148499)

巻号頁・発行日

no.141, pp.39-49, 1977-06

---

Analysing correlations among resistance at Froude number F_∇(= ∇/√<∇^<1/3>g>) =3.5, trim angles at F_∇=2.5 through 3.5, by using model test data in still water of the high speed craft, the clear correlation was found to exist between resistance at F_∇=3.5 and trim angle at F_∇=2.5. Therefore, the sequential unconstrained minimization technique was first applied to get the smallest total resistance hull form for each 30 minutes interval of trim angle change, and then followed the discussion concerning deviations arisen and resistance performance due to obtained hull form parameters. Using diagrams related to the total resistance at F_∇=3.5 and the trim angle at F_∇=2.5, we clarified finally the influence of the unit trim angle on the total resistance coefficient within high speed range.

著者

児玉 良明 角川 明 高橋 孝仁 石川 暁 川北 千春 金川 健 戸田 保幸 加藤 洋治 地本 晶彦 山下 和春 永松 哲朗

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.2002, no.192, pp.1-13, 2002 (Released:2007-05-30)

参考文献数

17

被引用文献数

5 2

---

This paper is the first half of the report on the study on microbubbles carried out by the SR239 project of the Shipbuilding Research Association of Japan, and describes the preparatory study for the full-scale experiment using a 116m-long ship. In the present study, first the skin friction reduction effect by microbubbles was investigated including the use of an array-of-holes plate for bubble generation, the effects of streamwise pressure gradient, surface curvature, and vertical plate, the sea-water effect, and the effect of bubble size. Bubble generators for the full-scale experiment were designed and built, and a preliminary injection experiment was carried out. Two new measuring devices for the full-scale experiment were developed; they are skin friction sensors and local void ratio sensors. Microbubble experiments were carried out in a 400m-long towing tank using a 50m-long flat plate ship, in order to obtain the scale effect data and to confirm the validity of the new devices for the full-scale experiment. The use of adhesives to fix measurement devices and cables on the hull surface was tested and established. The hydrodynamic fairing of the cables was also tested and established. Finally, a preliminary microbubble experiment using a small ship was carried out and the bubble behavior was observed.

著者

松村 竹実 浦 環

出版者

公益社団法人日本船舶海洋工学会

雑誌

日本造船学会論文集 (ISSN:05148499)

巻号頁・発行日

no.183, pp.91-100, 1998-06

被引用文献数

4 1

---

This paper proposes an artificial neural network system for regressive estimation of wave making resistance, which is significantly important in preliminary design of high-speed ship. The neural network can explicitly realize nonlinear mapping between hull form and wave making resistance. The system is composed of two kinds of neural networks ; Estimating Net and Descriptive Net. The Estimating Net learns the relation between hull form parameters and wave making resistance coefficients from a number of model-resistance test data. Consequently, when Froude Number, principal particular rations, and area curve parameters of a hull form are given, the Estimating Net of the learned data points in the hull form parameters space. It provides the information about the density of the learned data at the input point in the above parameters' space. In this paper, the test data of 62 models : Series 60, are used for the construction of the system. The leaning is successful and the results of playback calculation show good agreement with the original test data. Some applicable cases for non-learned hull forms are also explained. It is shown that the accuracy of the estimation is in accordance with the output of the Descriptive Net. When other model test data are available, it is easy to modify the constructed system, taking advantage of leaning ability of neural networks.

著者

胡 長洪 福地 信義 中島 徹

出版者

公益社団法人日本船舶海洋工学会

雑誌

日本造船学会論文集 (ISSN:05148499)

巻号頁・発行日

no.189, pp.127-135, 2001-06

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In many compartment natural-convection problems associate with functional design of beat transfer for ships and ocean structures, large temperature difference occurs between the surrounding walls. Examples of such heat transfer problems include a cabin of a passenger ship when the neighboring cabin is on fire, and reefer holds of a refrigerating cargo ship. In these situations, heat radiation exchange among the wall surfaces cannot be neglected if the wall emissivities are not very small. In this paper, a numerical study is reported on combined turbulent convection, heat radiation and conduction in a rectangular enclosure with all six surrounding walls having finite emissivity and conductance. The turbulent convection is computed by a large eddy simulation (LES) method. The emphasis of the study is on the effects of wall radiation exchange on turbulent natural convection in a rectangular enclosure. For comparison with the computation, a laboratory experiment is also carried out on a rectangular enclosure with one sidewall heated by electric heaters. The effect of wall radiation on the natural convection is investigated by changing the wall emissivities. Excellent agreement of temperature between numerical predictions and the experimental measurements is obtained.

著者

尾崎 雅彦 南浦 純一 北島 良則 溝上 宗二 竹内 和久 畠中 勝則

出版者

公益社団法人日本船舶海洋工学会

雑誌

日本造船学会論文集 (ISSN:05148499)

巻号頁・発行日

no.187, pp.185-192, 2000-06

被引用文献数

3

---

Ocean sequestration of the captured CO_2 from fossil fuel burning is a possible option to mitigate the increase of CO_2 concentration in the atmosphere. It can isolate huge amount of CO_2 from the atmosphere for long time in relatively low cost, if it is acceptable from the viewpoint of the oceanic environmental impact. The dissolution type treated in this paper is based on the idea that CO_2 dissolved and sufficiently diluted in seawater does no more harms than slightly increasing the concentration of CO_2 already contained in the seawater. The concept of CO_2 dispersion in the ocean depths by ship is a promising implementation for the efficient dilution. That is, liquefied CO_2 is delivered by ship to the site and injected into ocean depths of 1,000 to 2,500m with a suspended and towed pipe by a slowly moving ship. The constant movement of releasing point of CO_2 causes no stagnation and accumulation of CO_2 in seawater. The released CO_2 will form plenty of droplets, and then they rise gently due to the buoyancy, while reducing in the size to disappear by dissolution in the ambient seawater. Since the turbulent diffusion in the intermediate ocean is dominant horizontally, use of the vertical journey of CO_2 droplets will be very effective for the initial dilution. Thus, authors have good prospects for the dilution ratio of one to a hundred thousands in a couple of hours after injection on an engineering realistic scale, by means that the initial size of droplets is controlled. Drop formations from a fixed nozzle are investigated referring the common knowledge on textbooks. And the possibility of generating relatively large size of droplets from a moving nozzle is experimentally studied. As a result, it is found that the horizontal nozzle towed by the slowly moving ship is promising for the control of the drop formations in a realistic scale .

著者

茂里 一紘 土井 康明 伊藤 昌広 岸本 由豆流

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.1991, no.169, pp.143-149, 1991 (Released:2009-09-04)

参考文献数

4

---

A semi-submersible displacement-type high-speed ship with wings is studied on its stability control by flaps.The vehicle, called HSV (High-speed Semi-submersible Vehicle with wings) here, is consisting of a main hull, main and tail wings with flaps, and a strut to support the super-structure. The HSV floats at a certain draft like a conventional ship while it is still, and it submerges when it moves forward due to a downward lift force induced by the main wings. HSV cannot have enough upright moment as conventional ships because of its small waterplane area. HSV is expected to be stable by an active control of flaps.Experiments are carried out to study about the possibility of the stability control by the flaps of the main and tail wings. An automatic control system is developed under which HSV is towed with the heaving, rolling, pitching and yawing motions free. The angles of attack of flaps are controlled after the measured ship motion in order to stabilize the motion.It is concluded that, although the control is not perfect due to the mechanical limitation of the used system, HSV can run stably by the active control of the flaps. The experiments among regular waves made clear that waves could not be a serious factor for the stability of HSV.

著者

永井 保 浜本 剛実 守 国夫

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.1972, no.131, pp.281-295, 1972 (Released:2009-09-04)

参考文献数

10

被引用文献数

2 2

---

Taking pictures of the motion of a water surface at the impact of flat and concaved rectangular plates on the water, we obtained the phenomena which the air was entrapped and compressed between the water surface and plate surface, while blowing out through the contact part of both surfaces. In order to develop the equation of air motion reasonably, we took the energy dissipation due to volume change of entrapped air into consideration, hence, an unknown coefficient was herein introduced. It was suitably determined from measured data by the dropping test already done by one of authors. The aspect ratio of rectangular plate was chosen beyond about three, and plates have one-third or full scale when compared with the plate panels of both destroyers and torpedo boats. We finally obtained the experimental formula of impulsive water pressure covering M/ρl2 from about 2 through 7, which might be considered most useful for practical purpose.To get the elasto-plastic response of concaved rectangular plates, the damping effect due to compressed air was also introduced into the theoretical treatment, and this damping coefficient was approximately determined so as to satisfy the critical damping condition of the plate, such as the case of flat plates. We therefore obtained the experimental formula of the response.Within plate scantlings used in our experiment, if the plate is repeatedly dropped on the water from the same height the induced concavity will finally converge to the certain magnitude. And hence, applying those two formulae obtained above to solve such phenomena, reasonable coincidences concerning concavities after each drop were obtained between the computed results by numerical analysis and measured data.