1991 Fiscal Year Final Research Report Summary
Study on a High Speed Semi-Submersible Ship.
| Project/Area Number |
01460168
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
船舶抵抗・運動性能・計画
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| Research Institution | Hiroshima University |
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Principal Investigator |
MORI Kazu-hiro Hiroshima Univ., Fac. of Eng., Professor, 工学部, 教授 (90011171)
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| Co-Investigator(Kenkyū-buntansha) |
HOTTA Takio Hiroshima Univ., Fac. of Eng., Associate professor, 工学部, 助教授 (30034359)
HIGO Yasushi Hiroshima Univ., Fac. of Eng., Associate professor, 工学部, 助教授 (20156582)
DOI Yasuaki Hiroshima Univ., Fac. of Eng., Associate professor, 工学部, 助教授 (10134454)
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| Project Period (FY) |
1989 – 1991
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| Keywords | Semi-Submersible High-Speed Ship / Boundary Element Method / Free-Surface Flow / Micro-Bubble Method / Stable Running |
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| Research Abstract |
In the present project, three items related to the high speed ship are mainly studied ; (1) free-surface flow computation by the boundary element method, (2) model experiments for the stable running and motion control, and (3) reduction of the frictional resistance by micro-bubble injection. Following conclusions and findings are mentioned.
1. Some new methods are introduced for the treatments of free-surface, downstream and Kutta conditions and it is proved that the method is effective. Several cases for the semi-submersible high-speed ship are simulated to find interesting phenomena on the interaction between the submerged lifting surface and free-surface flows.
2. An experiment to confirm stable running is carried out by making use of a towed model where heaving, pitching and rolling motions are free and the PD control is introduced. A free running test where all the motions are free is also carried out to confirm that a stable running is assured if a control is introduced properly. The sea-worthiness of the semi-submerged ship is proved good through the experiments among waves.
3. An experiment is carried out by marking use of a separable model to determine the reduction of resistance due to the micro-bubble injection. The resistance reduces when the velocity and the quantity are above a certain level. However, the required work to inject the bubble is larger than the saved resistance because of the small size of the model. This may not be serious for the actual ship.
Through the present studies on the hydrodynamic aspects of the high-speed semi-submersible ship, it can be concluded that such a type of high speed ship is prospective. More experiments on free running are necessary for further studies.
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