| Project/Area Number |
09651011
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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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 | HOKKAIDO UNIVERSITY |
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Principal Investigator |
KARASUNO Keiichi Hokkaido Univ., Fac. of Fis., Pro., 水産学部, 教授 (80031467)
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| Co-Investigator(Kenkyū-buntansha) |
MAEKAWA Kazuyoshi Hokkaido Univ., Fac. Of Fis., Inst., 水産学部, 助手 (80250504)
JANUMA Syunji Hokkaido Univ., Fac. Of Fis., Asso. Pro., 水産学部, 助教授 (30187588)
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| Project Period (FY) |
1997 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 1999: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1998: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1997: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Keywords | Hydrodynamic forces in maneuvering motion / Towing test with ship models / Transitional characteristics of hydrodynamic forces / 拘束曳航試験 |
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| Research Abstract |
The interim standards of ship maneuverability by IMO are badly in need of the prediction of ship maneuverability at design stage. In this research project for the prediction, we measured the transitional characteristics of hydrodynamic forces acting on ship hulls and tried to estimate the hydrodynamic forces in steady state from the transitional characteristics. First, we studied a method to estimate the added mass of a model ship, which is indispensable to analyze hydrodynamic force acting on the ship in motion. From this study, we developed a simple method to measure the added mass by a model experiment and made out a quick chart of the added mass estimation for block type ship. We also developed a method to estimate the added mass by using CFD, which does not need to carry out model experiments. Next, we studied about a component-type mathematical model of hydrodynamic forces in maneuvering motion to comprehend the mechanism of the forces. In this research project, we carried out oblique towing tests of several ship models to understand the transitional characteristics of hydrodynamic forces. From the analysis of time histories of hydrodynamic forces by using the component-type mathematical model, we got the following concluding remarks.
1. The cross flow drag component is a significant factor of the transitional effect. At the beginning of constant velocity in motion, the cross flow drag of the ship that has a rectangular cross section, reaches quickly to a steady state. On the other hand, the cross flow drag of more practical ship needs much time to be stead state.
2. The transitional effect of the viscous lift component is more prominent at the bow rather than the stern. But the effect is very little in total hydrodynamic force.
3. From the results described above, it seems to be possible to estimate roughly the hydrodynamic forces in steady state from the transitional characteristics in the oblique towing motion.
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