2023 Fiscal Year Final Research Report
Proposal of feasible measures to satisfy the similarity of river hydraulic model experiments including seepage flow
Project/Area Number |
21K04270
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Research Category |
Grant-in-Aid for Scientific Research (C)
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Allocation Type | Multi-year Fund |
Section | 一般 |
Review Section |
Basic Section 22040:Hydroengineering-related
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Research Institution | Nagaoka University of Technology |
Principal Investigator |
YANG Hongxuan 長岡技術科学大学, 工学研究科, 助教 (00324004)
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Co-Investigator(Kenkyū-buntansha) |
細山田 得三 長岡技術科学大学, 工学研究科, 教授 (70262475)
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Project Period (FY) |
2021-04-01 – 2024-03-31
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Keywords | 河川構造物 / 浸透流 / フルード相似 / 不安定 / パイピング |
Outline of Final Research Achievements |
Theoretical similarity conditions to simultaneously satisfy similarities of river flow and seepage flow were derived, and feasible similarity requirements and countermeasures for hydraulic model experiments of river flow including seepage flow were examined using numerical models verified by model experiments and seepage flow visualization experiments. For laminar seepage flow, it was found that if the permeability is similar, the pressure is similar, and even if the permeability is not strictly similar, the pressure similarity is not significantly broken. In the case of turbulent seagape flow, the similarity condition is strict. The permeability of the model follows follow the permeability of the real object on the flow velocity scale, and it is also necessary to satisfy the condition that FL_model = FL_real object. F is the Forchheimer coefficient and L is the representative length.
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Free Research Field |
水工学
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Academic Significance and Societal Importance of the Research Achievements |
浸透流の試験は地盤専門の方が行う場合が多い.一方、河川の流れの相似は水工学専門の方が考えることである.河川構造物の場合,地盤中の浸透流が流れとして無視出来ても圧力の連続的伝播という意味で無視できず,河川流と同時に扱う必要があり,河川流の相似と矛盾しない相似が求められる.浸透流速が小さいだけに,浸透流を含む模型実験において浸透流が相似せず圧力相似の喪失は浸透流を扱わない水工学専門家が見落としがちであり,対策もないのが現状である. 浸透流を含む河川の模型実験に,浸透流にも相似性を持たせることができれば,学術的に意味があるだけでなく、模型実験がより実物と近い現象になり、河川防災に重要な社会貢献となる.
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