| Project/Area Number |
62850080
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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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 | UNIVERSITY OF OSAKA PREFECTURE |
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Principal Investigator |
HIMENO Yoji UNIV. OF OSAKA PREFECTURE, DEPT. OF NAVAL ARCHITECTURE, PROFESSOR, 工学部, 教授 (50081394)
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| Co-Investigator(Kenkyū-buntansha) |
NISHIO Shigeru UNIV. OF OSAKA PREF., DEPT. OF NAVAL ARCH., RESEARCH ASSISTANT, 工学部, 助手 (30208136)
TAKAMATSU Kenichiro UNIV. OF OSAKA PREF., DEPT. OF NAVAL ARCH., RESEARCH ASSISTANT, 工学部, 助手 (10081390)
HIRANO Susumu UNIV. OF OSAKA PREF., DEPT. OF NAVAL ARCH., LECTURER, 工学部, 講師 (70081388)
OKUNO Taketoshi UNIV. OF OSAKA PREF., DEPT. NAVAL ARCH., ASSOCIATE PROF., 工学部, 助教授 (60081395)
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| Project Period (FY) |
1987 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥4,600,000 (Direct Cost: ¥4,600,000)
Fiscal Year 1989: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1988: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1987: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Keywords | SHIP PERFORMANCE / MOTION IN WAVE / WAKE / VISCOUS FLOW |
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| Research Abstract |
The prediction of ship propulsive performance in wave is one of the most important items in the assessment of the entire ship performances. The effect of the wake on the propulsive performance has been known to be predominant among the propusive factors. However, its prediction has been a difficult problem due to the viscous fluid effect on the wake. The objective of the present research is to elucidate the physical mechanism of the ship viscous wake in waves and to evaluate the reasonable prediction methods.
In the three-year period of the present research, the first year was devoted to the measurement of the oscillating stern flow velocities and its analysis. It was found that the mean wake decreases in the region where the amplitude of the oscillation becomes large.
In the second year, the computations based on the unsteady boundary layer assumption in the internal wake region and the potential flow outside were made to predict the change of the wake values due to the wave motion and the ship motion. The agreement with the experiment was quite well except for the region of large wake change.
The final year has been devoted to carry out the computations based on 2D Navier-Stokes equation for an oscillating elliptic cylinder at forward speed, which simulates the ship viscous wake flow in waves. The result of the computations shows a similar tendency with the measured wake values which was done in the first year.
It can be summarized that the present research has clarified the physical mechanism of the oscillating wake field at ship stern in its motions in waves, and attempted to predict the oscillating wake values. Research for the improvement of the prediction method still remains.
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