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Entrainment Phenomena in a Stratified Flow with Average Velocities and Turbulent Surface Layers

Research Project

Project/Area Number 09450186
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field 水工水理学
Research InstitutionHokkaido University

Principal Investigator

YOSHIDA Shizuo  Hokkaido Univ., Grad. School of Eng., Assoc. Prof., 大学院・工学研究科, 助教授 (30001324)

Co-Investigator(Kenkyū-buntansha) NISHIDA Shuzo  Osaka Univ., Grad. School of Eng., Assoc. Prof., 大学院・工学研究科, 助教授 (40172663)
Project Period (FY) 1997 – 1999
Project Status Completed (Fiscal Year 1999)
Budget Amount *help
¥4,100,000 (Direct Cost: ¥4,100,000)
Fiscal Year 1999: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1998: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1997: ¥2,300,000 (Direct Cost: ¥2,300,000)
KeywordsRiver mouth flow / Two layer flow / Salt wedge / Entrainment coefficient / Interfacial instability / Richardson number / Tide / Wind wave
Research Abstract

This report describes unsteady mixing mechanisms in highly stratified flow at river mouths. Wind, tide, flowrate and externally induced turbulence (from waves) are the factors considered here.
The following data were taken in studies of the lower 45 km of the Ishikari River, whose level is affected by the tide, in 1997 and 1998: 1) Automatic recordings of surface salinity for two months at six locations; 2) salinity at six depths in a vertical line for two weeks at two locations; 3) depth of the interface, using a sonic depth finder, at three locations for two months.
The results of the studies are summarized as follows: 1) During semidiurnal tides, the amplitude of the variation in position of the salt wedge interface is n times the tidal difference; n increases gradually from the mouth to about 7 km upstream, then reverses the increasing trend, diminishing to about zero at 26 km upstream. It was originally thought that the interface fluctuation reaches a maximum at 7 km upstream due to river topology, but the reason remains unknown. 2) The relation of surface salinity with wind has been explained by the observations of vertical salinity distribution. Diffusion of salt across the interface is augmented by increased wind, while the salt concentration gradient in the upper layer remains very low. This means that the salt entrained into the upper layer due to wind-induced processes is immediately distributed through the layer; ordinary diffusion processes can not be responsible for this. 3) Fluctuations in river flow speed with periods of 2.5 s and 10 - 20 s were observed between 0 and 4 m depth. Both fluctuations arise from wave action, but there was no interface at any of the times these fluctuations were observed, so they can not be caused by interface waves.

Report

(4 results)
  • 1999 Annual Research Report   Final Research Report Summary
  • 1998 Annual Research Report
  • 1997 Annual Research Report
  • Research Products

    (28 results)

All Other

All Publications (28 results)

  • [Publications] S.YOSHIDA: "Mixing Processes in Highly Stratified River"Coastal and Estuarine Studies. 54. 389-400 (1998)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] 吉田静男: "河口二層流に与える潮汐効果"土木学会北海道支部論文報告集. 54(B). 328-333 (1998)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] 吉田静男: "塩水楔形状に与える潮汐の影響"水工学論文集. 43. 875-880 (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] 古城則道: "河口二層流の潮汐変動予測"土木学会北海道支部論文報告集. 55. 184-190 (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] 吉田静男: "石狩川の密度成層構造と地形・気象・海象の関係―V"福田昭(福田水文センター株式会社). 220 (1998)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] 吉田静男: "石狩川の密度成層構造と地形・気象・海象の関係―VI"福田昭(福田水文センター株式会社). 186 (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] S. Yoshida, M. Ohtani, S. Nishida and P.F. Linden: "Mixing processes in a highly stratified river"Coastal and Estuarine Studies. 54. 389-400 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] S. Yoshida, K. Yokoo, Y. Nakamiti, T. Hashimoto: "Tidal effects on two layer river flow"Proceedings of JSCE Hokkaido Branch. 54(B). 328-333 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] S. Yoshida, S. Nishida, K. Yokoo. K. Ogiwara: "Tidal effect on the salt wedge shape"Proceedings of Hydraulic Engineering. 43. 875-880 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] N. Kojyou, S. shida: "Numerical analysis on the tidal response of two-layer flow at a river mouth"Proceedings of JSCE Hokkaido Branch. 55(B). 184-188 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] S. Yoshida, S. Nishida, K. Yokoo, Y. Nakamiti: "Topographical, meteorological, oceanographycal effects on Stratified river flow in Ishikari river (5)"Research Report of Fukuda Hydrologic Center CL. 1-220 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] S. Yoshida, S. Nishida, K. Yokoo, Y. Nakamiti: "Topographical, meteorological, oceanographycal effects on Stratified river flow in Ishikari river (6)"Research Report of Fukuda Hydrologic Center CL. 1-186 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] 吉田静男: "河口二層流に与える潮汐効果"土木学会北海道支部論文報告集. 54(B). 328-333 (1998)

    • Related Report
      1999 Annual Research Report
  • [Publications] 吉田静男: "Mixing Processes in Highly Stratified River"Coastal and Estuarine Studies. 54. 389-400 (1998)

    • Related Report
      1999 Annual Research Report
  • [Publications] 吉田静男: "河口二層流の潮汐変動予測"土木学会北海道支部論文報告集. 55. 184-189 (1999)

    • Related Report
      1999 Annual Research Report
  • [Publications] 吉田静男: "塩水楔形状に与える潮汐の影響"水工学論文集. 43. 875-880 (1999)

    • Related Report
      1999 Annual Research Report
  • [Publications] 古城 則道: "河口二層流の潮汐変動予測"土木学会北海道支部論文報告集. 55. 184-190 (1999)

    • Related Report
      1999 Annual Research Report
  • [Publications] 吉田静男: "石狩川の密度成層構造と地形・気象・海象の関係V"(株)福田水文センター、福田 昭. 153 (1998)

    • Related Report
      1999 Annual Research Report
  • [Publications] 吉田静男: "石狩川の密度成層構造と地形・気象・海象の関係VI"(株)福田水文センター、福田 昭. 200 (1999)

    • Related Report
      1999 Annual Research Report
  • [Publications] 吉田静男: "尻別河口成層密度流と地形・気象・潮汐の関係"佐藤政雄((社)北海道栽培漁業振興公社). 110 (1999)

    • Related Report
      1999 Annual Research Report
  • [Publications] 吉田静男: "石狩川の密度成層構造と地形・気象・海象の関係VII"福田 昭(福田水文センター). 210 (2000)

    • Related Report
      1999 Annual Research Report
  • [Publications] 吉田静男: "Mixing Processes in Highly Stratified River" Coastal and Estuarine Studies. 54. 389-400 (1998)

    • Related Report
      1998 Annual Research Report
  • [Publications] 吉田静男: "河口二層流の潮汐変動予測" 土木学会北海道支部論文報告集. 55. 184-189 (1999)

    • Related Report
      1998 Annual Research Report
  • [Publications] 吉田静男: "塩水楔形状に与える潮汐の影響" 水工学論文集. 43. 875-880 (1999)

    • Related Report
      1998 Annual Research Report
  • [Publications] 吉田静男: "石狩川の密度成層構造と地形・気象・海象の関係-V" 福田昭(福田小文センター株式会社), 200 (1999)

    • Related Report
      1998 Annual Research Report
  • [Publications] 吉田静男: "尻別川河口成層密度流と地形・気象・潮汐の関係" 佐藤政雄((社)北海道栽培漁業振興公社), 110 (1999)

    • Related Report
      1998 Annual Research Report
  • [Publications] 吉田静男: "河口二層流に与える潮汐効果" 土木学会北海道支部論文報告集. 54(B). 328-333 (1998)

    • Related Report
      1997 Annual Research Report
  • [Publications] 吉田静男: "石狩川の密度成層構造と地形・気象・海象の関係 V" (株)福田水文センター 福田 昭, 375 (1998)

    • Related Report
      1997 Annual Research Report

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Published: 1997-04-01   Modified: 2016-04-21  

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