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Open-Channel Turbulence Structure of Flow with Separation and Large Free-Surface Deformation

Research Project

Project/Area Number 12650514
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field 水工水理学
Research InstitutionKOBE UNIVERSITY

Principal Investigator

FUJITA Ichiro  Research Center for Urban Safety and Security, KOBE UNIVERSITY, Associate Professor, 都市安全研究センター, 助教授 (10127392)

Project Period (FY) 2000 – 2001
Project Status Completed (Fiscal Year 2001)
Budget Amount *help
¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2001: ¥600,000 (Direct Cost: ¥600,000)
KeywordsOpen-channel turbulence / Image analysis / PIV / Trench / Hyudraulic jump / Backward-facing step / Flow separation / Free surface / 水面変動
Research Abstract

Turbulence properties of an open-channel flow with a sudden change of bed elevation were experimentally investigated Using an image analysis method. In the present study, open-channel flows having a backward-facing step with or without a forward-facing step were treated. In the case with a forward-facing step, the elevation of the step was varied so that a non-symmetric concavity section was, formed in the middle of the channel, which we called a trench section. In the case of a single backward-facing step, turbulent flows with or without sand, roughness were investigated for comparison.
In the trench case, it was found that an oscillatory hydraulic jump is generated within the trench section for a narrow range of the trench aspect ratio. In $he beginning, this phenomenon was considered as a result of the interaction between separation vortices from the upstream step and water surface. However, it was made clear that the periodic oscillation was caused by the imbalance between the mean velocity and the speed of wave created just downstream of the forward-facing step for a certain flow condition. The turbulence properties within the trench section were clarified using the image analysis ,techniques referred to as the Particle Tracking Velocimetry (PTV) and the Particle Image Velocimetry (PIV). A high-speed video camera and a high resolution video camera were utilized for these purposes. It was made clear that the increase of energy dissipation is closely related to the level of turbulence in the trench section. For the case of a backward-facing step, it was found that the reattachment length becomes about twenty percent shorter when the bed was roughened by sand elements, -which is a new finding never reported, elsewhere.

Report

(3 results)
  • 2001 Annual Research Report   Final Research Report Summary
  • 2000 Annual Research Report
  • Research Products

    (18 results)

All Other

All Publications (18 results)

  • [Publications] 藤田一郎, 丸山達弥: "トレンチを有する開水路段落ち流れの特性"応用力学論文集. Vol.3. 745-752 (2000)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] 藤田一郎, 丸山達弥: "非対称トレンチ流れにおけるエネルギー損失"土木学会関西支部年次学術講演会講演概要. II-57-1-II-57-2 (2000)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Ichiro FUJITA: "Image Analysis of Open-Channel Flow at a Backstep Having a Trench"Proceedings of the 6th Asian Symposium on Visualization. (CD-ROM). (2001)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] 藤田一郎, 丸山達弥: "トレンチ付き落差工流れの水理特性"水工学論文集. 第45巻. 403-408 (2001)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] 丸山達弥, 藤田一郎, 中野正悟: "開水路非対称トレンチ部における振動跳水の特性"土木学会関西支部年次学術講演会講演概要. II-32-1-II-32-2 (2001)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Fujita, I. and Maruyama, T.: "Characteristics of open-channel backstep flow with a trench"Journal of Applied Mechanics JSCE. Vol.3(in Japanese). 787-796 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Fujita, I. and Maruyama, T.: "Energy dissipation at non-symmetric trench flow"JSCE Kansai Chapter, Proc. of Civil Engineering. II-57-I-II-57-2 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Fujita, I.: "Image Analysis of Open-Channel Flow at a Backstep Having a Trench"Proceedings of the 6th Asian Symposium on Visualization. CD-ROM. (2001)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Fujita, I. and Maruyama, T.: "Hydraulic characteristics of open-channel flow downstream of a falling work with a trench"Annual Journal of Hydraulic Engineering JSCE. Vol.45(in Japanese). 403-408 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Fujita, I., Maruyama, T. and Nakano, S.: "Characteristics of oscillating hydraulic jump at an open-channel trench"JSCE Kansai Chapter, Proc. of Civil Engineering. II-32-1-II-32-2 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] 藤田一郎, 丸山達弥: "トレンチを有する開水路段落ち流れの特性"応用力学論文集. Vol.3. 745-752 (2000)

    • Related Report
      2001 Annual Research Report
  • [Publications] 藤田一郎, 丸山達弥: "非対称トレンチ流れにおけるエネルギー損失"土木学会関西支部年次学術講演会講演概要. II-57-II-57-2 (2000)

    • Related Report
      2001 Annual Research Report
  • [Publications] Ichiro FUJITA: "Image Analysis of Open-Channel Flow at a Backstep Having a Trench"Proceedings of the 6th Asian Symposium on Visualization. (On CDROM). (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] 藤田一郎, 丸山達弥: "トレンチ付き落差工流れの水理特性"水工学論文集. 第45巻. 403-408 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] 丸山達弥, 藤田一郎, 中野正悟: "開水路非対称トレンチ部における振動跳水の特性"土木学会関西支部年次学術講演会講演概要. II-32-1-II-32-2 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] 藤田一郎: "トレンチ付き落差工流れの水理特性"水工学論文集. 第45巻. 403-408 (2001)

    • Related Report
      2000 Annual Research Report
  • [Publications] 藤田一郎: "開水路非対称トレンチ部における振動跳水の特性"土木学会関西支部年次学術講演会講演概要. (発表予定). (2001)

    • Related Report
      2000 Annual Research Report
  • [Publications] Ichiro FUJITA: "Image Analysis of Open-Channel Flow at a Backstep Having a Trench"Proceedings of the 6th Asian Symposium on Visualization. (発表予定). (2001)

    • Related Report
      2000 Annual Research Report

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Published: 2001-04-01   Modified: 2016-04-21  

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