| Project/Area Number |
63550329
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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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 | Osaka Prefecture University |
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Principal Investigator |
HIRANO Susumu Univ. of Osaka Pref., Engineering, Assistant Professor, 工学部, 講師 (70081388)
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| Co-Investigator(Kenkyū-buntansha) |
NISHIO Shigeru Univ. of Osaka Pref., Engineering, Research Associate, 工学部, 助手 (30208136)
TAKAMATSU Kenichiro Univ. of Osaka Pref., Engineering, Research Associate, 工学部, 助手 (10081390)
HIMENO Yoji Univ. of Osaka Pref., Engineering, Professor, 工学部, 教授 (50081394)
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| Project Period (FY) |
1988 – 1990
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| Project Status |
Completed (Fiscal Year 1990)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1990: ¥200,000 (Direct Cost: ¥200,000)
Fiscal Year 1989: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1988: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | Marine animal / Swimming motion / Standing wave form / Propulsive efficiency / Elastic model / Swimming experiment / 遊泳実験 / 準定常波動 / 尾びれ剛性 / 遊泳速度 / 屈曲振動体の遊泳フォ-ム / 細長体理論による数値計算 / 最適遊泳フォ-ム / 屈曲振動体模型の機構 / いるかの相似則 / いるか泳ぎ / 柔軟体自航模型 / 2節振動推進 |
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| Research Abstract |
There are the data that swimming speed of dolphin may be proportional to their body length (L). Low resistance, high propulsive efficiency or high muscle power has been realized.
The objective of the study is to determine experimentally with a model what swimming movements a dolphin can make which will give it high propulsive efficiency. This study is composed of three steps ; that is, the 1st step is to investigate swimming movements of real dolphin ; the 2nd step is to make a model ; the 3rd step is to make experiment with the model. At the 1st step, back stroke swimming movements of a dolphin were recorded and analyzed. From the results, it has shown that its movements are repetition of hogging and sugging, and looks like 2-node beam vibration, that is, its movemets belong to standing wave form.
Sir J. Lighthill were concluded theoretically as follows. For marine animals wishing to propel themselves efficiently and to attain high speed through water, it is necessary to pass a raveling wave beneath the body. But efficiency of the standing wave form here observed cannot exceed 50%. To clarify whether the standing wave form is efficient or not, a model which moves by standing wave form has been made.
For rigidly constructed model, there are problems on the strength of its body. Then, in this study, the elastic body construction was adopted, namely, piano-wires were employed for longitudinal strength member. The model length was 0.3m (1/10 scale). Size of piano-wire has decided in consideration of the law of similitude.
Both resistance tests and swimming tests were carried out in the towing tank. In the swimming tests, the maximum speed was 0.5m/sec.
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