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A Study on the Roughness Factor and the Stability of a Composite Channel.

Research Project

Project/Area Number 59550338
Research Category

Grant-in-Aid for General Scientific Research (C)

Allocation TypeSingle-year Grants
Research Field Hydraulic engineering
Research InstitutionTokyo Institute of Technology

Principal Investigator

ISHIKAWA Tadaharu  Associate Professor, Faculty of Engineering, 工学部, 助教授 (50159696)

Co-Investigator(Kenkyū-buntansha) TANAKA Masahiro  Researcher, Faculty of Engineering, 工学部, 助手 (90171800)
Project Period (FY) 1984 – 1985
Project Status Completed (Fiscal Year 1985)
Budget Amount *help
¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1985: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1984: ¥1,300,000 (Direct Cost: ¥1,300,000)
KeywordsComposite Channel / Lateral Mixing / Roughness Factor / 潅木 / 2次流
Research Abstract

The roughness factor of a composite channel increses when there is a strong lateral mixing between the low water channel and the flood plain. Therefore, We carried out an experiment on the lateral momentum mixing in a shallow open channel where the primary shear is in vertical. The following three types of flow were examined. (1) A couple of flows parallel to each other with a velocity difference. (2) A wake behind a piar. (3) A boundary layer on the side bank. Results showed that the lateral mixing in a shallow open channel is similar to the mixing of free turbulent flow and that the lateral eddy viscosity is proportional to the product of a lateral velocity difference and a lateral shear layer thickness. A shallow water equation accompanied by the above expression of the eddy viscosity led to a method of estimating the roughness factor of a composite channel.
The flow resistance of bushes which often glow between the low water channel and the flood plain was studied by a field observation and a flume experiment. It is noteworthy that the coupling of the motion of bushes and the lateral seiche makes an regular emition of voltexes and enlarges the resistance.
A numerical calculation method was developed to estimate a secondary circulation intensity which influences a large effect on the stability of the low water channel bank. Experiments verified that this method is useful especially in a natural river channel which is often bending in ancomprecated manner.
The above results are served for the planning and designing a composite channel.

Report

(1 results)
  • 1985 Final Research Report Summary
  • Research Products

    (8 results)

All Other

All Publications (8 results)

  • [Publications] 山崎真一,石川忠晴,金丸督司: 土木学会年次学術講演会概要集. 39-2. 473-474 (1984)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1985 Final Research Report Summary
  • [Publications] 田中昌宏,石川忠晴,木村聡: 土木学会年次学術講演会講演概要集. 41-2. 295-296 (1986)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1985 Final Research Report Summary
  • [Publications] 石川忠晴,鈴木研司,田中昌宏: 土木学会論文集. 375. 181-189 (1986)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1985 Final Research Report Summary
  • [Publications] 石川忠晴,田中昌宏: 水理講演会論文集. 31. 329-333 (1987)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1985 Final Research Report Summary
  • [Publications] Shinich YAMAZAKI, Tadaharu ISHIKAWA, Tokuji KANAMARU: "An Experimental Study on the Lateral Shear Field in an Open Channel." Proceedings of Annual Conference of the Japan Society of Civil Engineers.39-II. 473-474 (1984)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1985 Final Research Report Summary
  • [Publications] Masahiro TANAKA, Tadaharu ISHIKAWA, Satoahi KIMURA: "Lateral Mixing of a Thin Turbulent Flow between two parallel Plates." Proceedings of Annual Conference of the Japan Society of Civil Engineers.41-II. 295-296 (1986)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1985 Final Research Report Summary
  • [Publications] Tadaharu ISHIKAWA, Kenji SUZUKI, Masahiro TANAKA: "Efficient Numerical Analysis of an Open Channel Flow with a Secondary Circulation" Proceedings of Japan Society of Civil Engineers.375. 181-189 (1986)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1985 Final Research Report Summary
  • [Publications] Tadaharu ISHIKAWA, Masahiro TANAKA: "Studies on the Resistance Characteristics of the Bushes in the Open Channel Flow." Proceedings of Japanese Conference on Hydraulics.30. 329-333 (1987)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1985 Final Research Report Summary

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Published: 1987-03-31   Modified: 2016-04-21  

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