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Turbulent Structures and the Related Sediment Transport in Unsteady Open-Channel Flows

Research Project

Project/Area Number 06452273
Research Category

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

Allocation TypeSingle-year Grants
Research Field 水工水理学
Research InstitutionKYOTO UNIVERSITY

Principal Investigator

NEZU Iehisa  Kyoto University, Fac.of Eng., Assoc.Professor, 工学部, 助教授 (30109029)

Co-Investigator(Kenkyū-buntansha) GOTOH Hitoshi  Kyoto University, Fac.of Eng., Research Associate, 工学部, 助手 (40243068)
TOMINAGA Akihiro  Nagoya Institute of Tech., Fac.of Eng., Assoc.Professor, 工学部, 助教授 (60135530)
中川 博次  京都大学, 工学部, 教授 (60027216)
Project Period (FY) 1994 – 1995
Project Status Completed (Fiscal Year 1995)
Budget Amount *help
¥6,300,000 (Direct Cost: ¥6,300,000)
Fiscal Year 1995: ¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1994: ¥4,000,000 (Direct Cost: ¥4,000,000)
KeywordsOpen-Channel Flows / Unsteadiness / Space-time correlation structures / Coherent structure / Laser-Doppler anemometer / Conditional Sampling / Sand waves / Boils / 時空間相関構造 / 非定常流れ / 対数則分布
Research Abstract

In open-channel flows such as rivers and estuaries, various coherent vortices are often observed and greatly affect sediment transport. In the inner region which is very near the bed, bursting phenomena occur quasi-periodically and sustain the turbulence. On the other hand, in the outer region which is near the tree surface, a kolk-boil vortex occurs.
There exists a strong upward-tilting streamwise vortex motion, called the "kolk" , near the bed, in a analogy to a tomado motion in the atmosphere, and the kolk vortex develops up to the free surface and then becomes a "boil". A typical boil starts life with high sediment concentration, as a raised circular or oval patch on the water surface ; in the course of time, it widens and gradually settles back down toward the river level until it subsides completely and merges with the surrounding, less-agitated parts. Such coherent vortices are generated especially in flood rivers.
Therefore, it is very important to investigate unsteadiness effects on the turbulent structures and the coherent structures in unsteady open-channel flows so that the growing process of the dunes and the behavior of the suspended sediment can be explained dynamically. The authors have investigated turbulent structures in unsteady open-channel flows. It has been clarified that the unsteadiness has significant effects on the outer region near the free surface. The time variations of turbulent structure in the outer region and comparison with unsteady duct flow which has no free surface have examined.
Furthermore, the detailed turbulent flow structures over the actual form of sand dunes were measured accurately by making use of two sets of fiber-optic laser Doppler anemometers (FLDA) and automatic traversing system. The three-dimensional structures of coherent vortices generated behind the dune crest and the reattachment point were measured accurately.

Report

(3 results)
  • 1995 Annual Research Report   Final Research Report Summary
  • 1994 Annual Research Report
  • Research Products

    (33 results)

All Other

All Publications (33 results)

  • [Publications] Iehisa NEZU: "Experimantal Study on Turbulent Structures in Unsteady Open-Channel Flows," Proc. of Fundamentals and Advancements in Hydraulic Measurements and Experimentation, ASCE,. 1. 185-194 (1994)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Iehisa NEZU: "Coherent Structures in Compound Open-Channel Flows by Making Use of Particle-Tracking Visualization Technique," Proc. of Fundamentals and Advancements in Hydraulic Measurements and Experimentation, ASCE. 1. 406-415 (1994)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Iehisa NEZU: "Compound Open-Channel Turbulence and its Role in River Environment-Significance of Secondary Currents-," 9th Congress of the Asian and Pacific Division of the International Association for Hydraulic Research,Keynote Lecture,. 1-14 (1994)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Iehisa NEZU: "Turbulence Measurements in Unsteady Free-Surface Flows," Flow Measurement and Instrumentation, Butterworth-Heinemann,. 6. 49-59 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Iehisa NEZU: "General Log-Law and Turbulence Characteristics in Unsteady Depth-Varying Free-surface Flows," Proc. of 10th Symp. on Turbulence Shear Flows, The Pennsylvania State University,. 1. P1.1-P1.6 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Iehisa NEZU: "Turbulence Structure and Secondary Currents in Compound Open-Channel Flows with Variable-depth Flood Plains," Proc. of 10th Symp. on Turbulence Shear Flows, The Pennsylvania State University. 1. 7.7-7.12 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Nezu, I.: "Secondary Currents and Exchange Processes in Compound Open-Channel Flows," Proc.of 26th Congress of LAHR, London,. 1. 45-50 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Nezu, I.: "Turbulent Stuctures of Shear Layer over Cavity Using Fiber-Optic LDA," Proc.of 26th Congress of LAHR, London,. 1. 397-402 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Tominaga, A.: "Hydraulic Characteristics of Unsteady Flow in Open Channels with Flood Plains," Proc.of 26th Congress of LAHR, London,. 1. 373-378 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Tominaga, A.: "A modified k-EV turbulence model for turbulent flow over strip roughness in open channel," Proc.of the Int. Symp. on Mathematical Modelling of Turbulent Flows, Tokyo,. 339-344 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Nezu, I.: "Experimantal Study on Turbulent Structures in Unsteady Open-Channel Flows" Proc.of Fundamentals and Advancements in Hydraulic Measurements and Experimentation. ASCE. 185-194 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Nezu, I.: "Coherent Structures in Compound Open-Channel Flows by Making Use of Particle-Tracking Visualization Technique" Proc.of Fundamentals and Advancements in Hydraulic Measurements and Experimentation. ASCE. 406-415 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Nezu, I.: "Compound Open-Channel Turbulence and its Role in River Environment- Significance of Secondary Currents -" 9th Congress of the Asian and Pacific Division of the International Association for Hydraulic Research, Keynote Lecture. Syngapore. 1-14 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Nezu, I.: "Turbulence Measurements in Unsteady Free-Surface Flows" Flow Measurement and Instrumentation, Butterworth-Heinemam. vol.6, No.1. 49-59 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Nezu, I.: "General Log-Law and Turbulence Characteristics in Unsteady Depth-Varying Free-surface Flows" Proc.of 10th Symp.on Turbulence Shear Flows, The Pennsylvania State University. No.P1.1-P1.6. (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Nezu, I.: "Turbulence Structure and Secondary Currents in Compound Open-Channel Flows with Variable-depth Flood Plains" Proc.of 10th Symp.on Turbulence Shear Flows, The Pennsylvania State University. 7.7-7.12 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Nezu, I.: "Secondary Currents and Exchange Processes in Compound Open-Channel Flows" Proc.of 26th Congress of IAHR,London. vol.1. 45-50 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Nezu, I.: "Turbulent Structures of Free Shear Layr over Cavity Using Fiber-Optic LDA" Proc.of 26th Congress of IAHR,London. vol.1. 397-402 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Tominaga, A.: "Hydraulic Characteristics of Unsteady Flow in Open Channels with Flood Plains" Proc.of 26th Congress of IAHR,London. vol.1. 373-378 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Tominaga, A.: "A modified k-E<square root> turbulence model for turbulent flow over strip roughness in open channel" Proc.of the Int.Symp.on Mathematical Modelling of Turbulent Flows, Tokyo. 339-344 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] 祢津家久: "加速流および減速流の解析手法とその乱流特性" 土木学会論文集. 509. 89-98 (1995)

    • Related Report
      1995 Annual Research Report
  • [Publications] 祢津家久: "自由水面領域の非定常乱流特性に関する研究" 土木学会論文集. 509. 121-130 (1995)

    • Related Report
      1995 Annual Research Report
  • [Publications] 祢津家久: "開水路乱流の粘性底層および壁面領域に及ぼす非定常効果" 水工学論文集. 39. 833-838 (1995)

    • Related Report
      1995 Annual Research Report
  • [Publications] Iehisa Nezu: "Turbulent Measurements in Unsteady Free surface Flows" Flow Measurement and Instrumentation, Butterworth-Heinemann,. vol. 6,. 49-59 (1995)

    • Related Report
      1995 Annual Research Report
  • [Publications] Iehisa Nezu: "General Log-Law and Turbulence Characteristics in Unsteady Depth-Varying Free-surface Flows," Proc. of 10th Symp. on Turbulence Shear Flows,. vol. 1. P1. 1-P1. 6 (1995)

    • Related Report
      1995 Annual Research Report
  • [Publications] Iehisa Nezu: "Secondary Currents and Exchange Processes in Compound Open-Channe Flows," Proc. of 26th Congress of IAHR, London,. vol. 1. 45-50 (1995)

    • Related Report
      1995 Annual Research Report
  • [Publications] 祢津家久: "水理学・流体力学" 朝倉書店, 195 (1995)

    • Related Report
      1995 Annual Research Report
  • [Publications] Nezu,I: "Experimantal Study on Turbulent Structurres in Unsteady Open-Channel Flows" Proc.of Fundamentals and Advancements in Hydraulic Measurements and Experimentation,ASCE. 185-194 (1994)

    • Related Report
      1994 Annual Research Report
  • [Publications] 裲津家久: "非定常開水路流れの乱流構造に関する実験的研究" 土木学会論文集. No.491/II-27. 81-88 (1994)

    • Related Report
      1994 Annual Research Report
  • [Publications] 裲津家久: "開水路の非定常流れの乱流構造" 第26回乱流シンポ論文集. 270-273 (1994)

    • Related Report
      1994 Annual Research Report
  • [Publications] 裲津家久: "開水路乱流の粘性底層および壁面領域に及ぼす非定常効果(掲載予定)" 水工論文集. 第39巻. (1995)

    • Related Report
      1994 Annual Research Report
  • [Publications] 裲津家久: "加速流および減速流の解析手法とその乱流特性" 土木学会論文集. No.509. 89-97 (1995)

    • Related Report
      1994 Annual Research Report
  • [Publications] 裲津家久: "自由水面領域の非定常乱流特性に関する研究" 土木学会論文集. No.509. 121-130 (1995)

    • Related Report
      1994 Annual Research Report

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Published: 1994-04-01   Modified: 2016-04-21  

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