2000 Fiscal Year Final Research Report Summary
Study on Scale Effect of the Resistance due to Stem Wave Breaking
| Project/Area Number |
11650945
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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 | Hyogo University of Teacher Education |
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Principal Investigator |
YAMANO Tadao Hyogo University of Teacher Education, Life Studies, Professor, 学校教育学部, 教授 (90304138)
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| Co-Investigator(Kenkyū-buntansha) |
SUZUKI Toshio Osaka University, Graduate school of Engineering, Professor, 大学院・工学研究科, 教授 (80029107)
MIYATA Hideaki The University of Tokyo, Graduate school of Engineering, Professor, 大学院・工学研究科, 教授 (70111474)
KURATANI Fumiyasu Hyogo University of Teacher Education, Life Studies, Associate Professor, 学校教育学部, 助教授 (00294265)
IWASAKI Yasunon Kawasaki Heavy Industries Ltd., Initial Design, Manager (researcher), 基本設計部, グループ(研究者)
OKUNO Taketoshi Osaka Prefectural University, Graduate school of Engineering, Professor, 大学院・工学研究科, 教授 (60081395)
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| Project Period (FY) |
1999 – 2000
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| Keywords | Stem waves / Forward-oriented wave breaking / Remained following waves / Resistance / Scale effect / Flow velocity distribution at stem end / Boundary layer / Wave height |
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| Research Abstract |
(1) Clarification of the water flow structure just behind a transom stem
The detailed observation of water flow just behind a transom stem has clarified that reverse flow exists on water surface there and that the reversed flow is blocked out by the stem end and then flows along the stem end towards both sides and finally goes out into side flow. It has been also exprimentally confirmed that the reverse flow is generated as a result of forward-oriented wave breaking.
(2) Development of methods to treat forward-oriented wave breaking
Water flow just behind a transom stem has been approximated with trochoidal wave. Criteria for forward-oriented wave breaking occurrence have been proposed. Based on these, a method to estimate what thickness of flow layer under water surface breaks and an equation to estimate resistance due to forward-oriented wave breaking have been developed.
(3) Clarification of forward-oriented wave breaking characteristics
Studies of the phenomenon by the methods developed in 2 have clarified that the phenomenon is much affected by the vertical flow speed distribution at stem end as assumed at the start of this study, it has, therefore, scale effect and non-dimensional coefficient of resistance due to the phenomenon decreases with increase of model ship size. On the other hand, it has been clarified that height of remained following waves, which is generated at stem end, not broken and propagated afterwards, increases with increase of model ship size to the contrary.
(4) Study plan from now
Remained fallowing waves is to be studied at first. Next, scale effect of stem waves which consist of two components different in characteristics forward-oriented wave breaking and remained following waves is to be studied by the methods developed.
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