| Project/Area Number |
15360465
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Naval and maritime engineering
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| Research Institution | Osaka University |
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Principal Investigator |
UMEDA Naoya Osaka University, Graduate School of Engineering, associate professor, 大学院・工学研究科, 助教授 (20314370)
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| Co-Investigator(Kenkyū-buntansha) |
HASEGAWA Kazuhiko Osaka University, Graduate School of Engineering, professor, 大学院・工学研究科, 教授 (60106804)
ISIDA Shigesuke National Maritime Research Institute, Maritime Safety Department, senior research engineer, 海上安全研究領域, 上席研究員 (30360712)
MATSUDA Akihiko Fisheries Research Agency, National Research Institute of Fisheries Engineering, senior researcher, 水産工学研究所・漁業生産工学部, 主任研究官 (10344334)
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| Project Period (FY) |
2003 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥6,600,000 (Direct Cost: ¥6,600,000)
Fiscal Year 2005: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 2004: ¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2003: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Keywords | parametric rolling / prevention device / container ship / bifurcation / fishing vessel / sponson / anti-rolling tank / restoring variation / 平均法 / 数値シミュレーション / 不規則波 / 発生条件 / 許容振幅 / ポストパナマックスコンテナ船 / 自由航走模型実験 / 長波頂不規則波 / 短波頂不規則波 / 復原力変動 / 造波 / ストリップ法 / フルードクリロフ仮説 / 分岐解析 / ポアンカレ写像 |
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| Research Abstract |
Firstly, to understand parametric rolling, an averaging technique was applied to an uncoupled mathematical model of roll and then threshold of parametric rolling and its bifurcation structures were identified. The restoring variation term, which is involved in the mathematical model, was examined with captive model tests for two container ships. As a result, it was shown that a conventional Froude-Krylov component on its own is not sufficient and the wave-making and hydrodynamic lift components are indispensable.
Secondly, free-running experiments with a post-Panamax container ship model were conducted in regular, long-crested irregular and short-crested irregular waves. Here parametric rolling with the amplitude of about 20 degrees in head and bow seas was recorded and the effects of operational and environmental aspects were identified.
Thirdly, for the trawler that suffered parametric rolling with the amplitude of 21 degrees in head seas without forward speed, the numerical analysis with a 6 degrees-of-freedom model demonstrated that the restoring variation as the Froude-Krylov component is negligibly small and the relationship between natural roll and pitch period is crucial.
Finally, based on the obtained knowledge mentioned above, two types of anti-parametric rolling devices were proposed : one is midship sponsons for reducing the restoring variation and the other is an anti-rolling tank for increasing roll damping. These devices were installed in the container ship model and then a free-running experiment was carried out. The results demonstrate that sponsons that is 11.7% of the ship breadth in wide reduce 25% of parametric roll amplitude and the anti-roll tank of that weight is 3.2% of the ship displacement completely exclude parametric rolling. In addition, the numerical study indicated parametric roll of the trawler can be reduced by changing the pitch gyro radius.
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