| Project/Area Number |
07455396
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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 |
船舶工学
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| Research Institution | OSAKA UNIVERSITY |
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Principal Investigator |
NAITO Shigeru OSAKA UNIV., Dept.of NAOE Professor, 工学部, 教授 (20093437)
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| Co-Investigator(Kenkyū-buntansha) |
KIHARA Hajime OSAKA UNIV., Dept.of NAOE Assistant, 工学部, 助手 (40283717)
TAKAGI Ken OSAKA UNIV., Dept.of NAOE Assoc.Professor, 工学部, 助教授 (90183433)
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| Project Period (FY) |
1995 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥6,100,000 (Direct Cost: ¥6,100,000)
Fiscal Year 1996: ¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1995: ¥3,800,000 (Direct Cost: ¥3,800,000)
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| Keywords | Nonlinear Wave Motions / Deck Wetness / Flair Lines / Knuckle Lines / Nonmemory Nonlinear Transformation / ノンリニアー・ノンメモリー非線型変換 |
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| Research Abstract |
This research is to investigate the wave height on a hull surface with numerical results of nonlinear free surface elevations and experimental results in the small tank. Boundary Element Method is used to solve the field equations. Introducing the slender body approximation, the problem becomes a two-dimensional initial-boundary value problem and it can be solved in the time-domain by Mixed Eulerian-Lagrangian Methods.
The experimental investigation was carried out with three frigate models whose above water bow forms were different respectively. The investigation consists of three tests including restrained in still water, forced oscillation in still water and restrained in regular waves. For visualizing the free surface the illuminating wetted surface method is introduced and unsteady wave profiles as well as steady ones are measured as image data. Moreover, the data are transformed into time histories of wave height as each station. A harmonic analysis is carried out to analyze time histories data. The effect of above water bow form is recognized as the difference of wave height.
This procedure can take account of the three dimensional hull form above or below water surface and leads to a powerful procedure for a design of the above water bow form.
Also from the point of probabilistic theory, a mean and variance values and spectrum of a strong nonlinear time history are derived, which theory is also useful for initial design stage.
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