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River Plume Dynamics in Estuary

Research Project

Project/Area Number 03650423
Research Category

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

Allocation TypeSingle-year Grants
Research Field Hydraulic engineering
Research InstitutionOsaka University

Principal Investigator

NAKATSUJI Keiji  Osaka University, Dept. of Civil Engineering, Associate Professor, 工学部, 助教授 (10029324)

Project Period (FY) 1991 – 1992
Project Status Completed (Fiscal Year 1992)
Budget Amount *help
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1992: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1991: ¥1,300,000 (Direct Cost: ¥1,300,000)
KeywordsRiver plume / Plume spreading / Eddy viscosity / Density current / Earth's rotation / Coastal jet / Tidal flow / Three-dimensional numerical experiment / 河川プル-ム / 潮汐 / 三次元 / 数値実験
Research Abstract

Buoyant surface discharges into stagnant waters such as river plume and thermal plume are characterized by the three-dimensional structure of flow and density fields, which is for the most part controlled by horizontal pressure gradients and the stratification resulting from the density difference between discharged and receiving waters as well as momentum fluxes. Furthermore, their behaviors may change depending on the flow and density fields of ambient coastal seas and the geographical features near the river mouth. A three-dimensional, primitive numerical model with a free water surface is developed for examining the river plume spreading. Turbulent shear stresses and turbulent buoyant fluxes are expressed in terms of the eddy viscosities and diffusivities, in which the stratification effects are taken into account with empirical formulae through the comparison of numerical results with published experimental data.
The model predictions are compared with experimental results of river … More plumes with small densimetric Froude numbers, field observation results performed in the Akashi River, and the infrared image of the YodoRiver in flood. As a result, the mechanism peculiar to river plume spreading near the river mouth is clarified; that is, the flow acceleration, the divergence of river water and the lift off phenomena. The numerical model has been applied to river plumes discharged into cross flows and into complicated geographical features. In particular, the effects of spreading angle of river mouth topology on the three-dimensional structure of river plumes are evaluated by using a k-epsilon turbulence model from the scientific point of view.
On a larger scale, the Rossby deformation radius, the earth's rotation in addition to the buoyancy are the major forces that cause a strong geostrophic along-shore current. Consequently, the Yodo River plume flows to the right along the coastal line of Kobe and Awaji Island while forming a narrow coastal jet in the case of flood. The computed density field shows good agreement with the infrared image taken by the NOAA satellite during the flood flow of typhoon 8210. If there is a tidal flows, however, its producing current exceeds the density-driven current, enhancing the tidal excursion of the river plume unless the propagation speed of the coastal jet is too high. Instead, the density effect assists in the formation of the tidal residual current system. Less

Report

(3 results)
  • 1992 Annual Research Report   Final Research Report Summary
  • 1991 Annual Research Report
  • Research Products

    (21 results)

All Other

All Publications (21 results)

  • [Publications] 中辻 啓二: "表層密度流の三係元数値実験" 土木学会論文集. 434/II-16. 19-28 (1991)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1992 Final Research Report Summary
  • [Publications] 中辻 啓二: "河川プールムの拡がり特性とその物理機構" 土木学会論文集. 434/II-16. 29-36 (1991)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1992 Final Research Report Summary
  • [Publications] 中辻 啓二: "淀川洪水流の振舞いに及ぼす密度流と潮流の相乗効果" 海岸工学論文集. 38. 195-199 (1991)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1992 Final Research Report Summary
  • [Publications] K.NAKATSUJI: "Effects of Tidal Modulation on River Plume Spreading" Hydraulic and Environmental Modelling:Estuarine and River Waters (Ashgate). 299-309 (1992)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1992 Final Research Report Summary
  • [Publications] 中辻 啓二: "河口周辺部における河川流出流の流動構造" 土木学会論文集. 440/II-22. 31-38 (1993)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1992 Final Research Report Summary
  • [Publications] 中辻 啓二: "大阪湾で観られるフロント現象に関する数値実験" 水工学論文集. 37. 313-318 (1993)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1992 Final Research Report Summary
  • [Publications] Nakatsuji, K: "Numerical Experiments of Three-Dimensional Buoyant Surface Discharges" Proc. JSCE. Vol.434/2-16. 19-28 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1992 Final Research Report Summary
  • [Publications] Nakatsuji, K: "Three-Dimensional River Plume Spreading" Proc. JSCE. Vol.423/2-16. 29-36 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1992 Final Research Report Summary
  • [Publications] Nakatsuji, K: "Synergetic Effects of Density Current and Tidal Flow on Behaviors of Yodo River Flood Flow" Proc. Coastal Engineering, JSCE. Vol.38. 195-199 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1992 Final Research Report Summary
  • [Publications] Nakatsuji, K: "Effects of Tidal Modulation on River Plume Spreading" Hydraulic and Environmental Modelling: Estuarine and River Waters, Ashgate. 299-309 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1992 Final Research Report Summary
  • [Publications] Nakatsuji, K: "Numerical Experiments of Behaviors of River Plume" Proc. JSCE. Vol.241/2-22. 31-38 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1992 Final Research Report Summary
  • [Publications] Nakatsuji, K: "Numerical Study on Frontal Phenomena Observed in Osaka Bay" Proc. Hydraulic Engineering, JSCE. Vol.37. 313-318 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1992 Final Research Report Summary
  • [Publications] 中辻 啓二: "表層密度流の三次元数値実験" 土木学会論文集. 434/II-16. 19-28 (1991)

    • Related Report
      1992 Annual Research Report
  • [Publications] 中辻 啓二: "河川プルームの拡がり特性とその物理機構" 土木学会論文集. 434/II-16. 29-36 (1991)

    • Related Report
      1992 Annual Research Report
  • [Publications] 中辻 啓二: "淀川洪水流の振舞いに及ぼす密度流と潮流の相乗効果" 海岸工学論文集. 38. 195-199 (1991)

    • Related Report
      1992 Annual Research Report
  • [Publications] K.Nakatsuji: "Effects of Tidal Modulation on River Plume Spreading" Hydraulic and Environmental Modelling:Estuarine and River Waters(Ashgate). 299-309 (1992)

    • Related Report
      1992 Annual Research Report
  • [Publications] 中辻 啓二: "河口周辺部における河川流出流の流動構造" 土木学会論文集. 440/II-22. 31-38 (1993)

    • Related Report
      1992 Annual Research Report
  • [Publications] 中辻 啓二: "三次元表層密度流の数値実験" 土木学会論文枝. 434ー/IIー16. 19-28 (1991)

    • Related Report
      1991 Annual Research Report
  • [Publications] 中辻 啓二: "河川プル-ムの拡がり特性とその物理機構" 土木学会論文集. 434ーIIー16. 29-36 (1991)

    • Related Report
      1991 Annual Research Report
  • [Publications] 中辻 啓二: "淀川洪水流の振舞に及ぼす密度流と潮流の相乗効果" 海岸工学論文集. 38. 186-190 (1991)

    • Related Report
      1991 Annual Research Report
  • [Publications] Nakatsuji,K.: "Effects of Tidal Modulation on River Plume Spreading" Proc.Intl.Conference on Hydraulic and Environthental Modelling in Coastal,Estuarine and River Waters. (1992)

    • Related Report
      1991 Annual Research Report

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Published: 1991-04-01   Modified: 2016-04-21  

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