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2004 Fiscal Year Final Research Report Summary

Structure Analysis and Control of Necklace Vortices Generated between Two Circular Cylinders Forming a Separating Cross

Research Project

Project/Area Number 14550168
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Fluid engineering
Research InstitutionTokuyama College of Technology

Principal Investigator

YAMADA Hidemi  Tokuyama College of Technology, Mechanical and Electrical Engineering, Professor, 機械電気工学科, 教授 (00116766)

Project Period (FY) 2002 – 2004
KeywordsFluids Dynamics / Crossed Two Circular cylinders / Gap Distance / Vortices Structure / Necklace Vortex / Three Dimensional Wake / Flow Visualization / Surface Pressure Distribution
Research Abstract

The three dimensional flow field area and the necklace vortices structure around two cylinders forming a separating cross were visualized using a dye injection method and a tracer particle method under the Reynolds number between 500 and 2000, and the surface pressure distribution on two circular cylinders was measured under the Reynolds number between 1000 and 8000 in detail to clarify the necklace vortex structures in uniform flow and the effects of the necklace vortex behavior on the fluid force into and on the separation flow from the cylinders. In addition, the relationship between the necklace vortex structure being made change by the gap distance and the pressure distribution on the surface of the cylinders was investigated.
It is found that the various patterns of the necklace vortices system are produced, depending on the gap distance "G" between two cylinders. In the case of the gap distance ratio "G/d" between 0 and 0.1, the boundary layer on the surface of the upstream cylinder separates and rolls up as a small necklace vortex in the front of the downstream cylinder, and the vortex system with 4 vortices is produced in the symmetrical plane of y/d=0. In the case of G/d=0.2-1.0, a pair of main necklace vortices grows in the gap space between two cylinders, and the 8 vortices system as total is produced. In the case of G/d=1.0-1.5, the pair of main necklace vortices starts vibrating as well as twin vortices behind a cylinder in the low Reynolds number. In the case of G/d=1.5-2.0, the behavior of necklace vortices behind the upstream cylinder is similar to that of Karman vortices under the low Reynolds number.

  • Research Products

    (6 results)

All 2005 2004 2003

All Journal Article (6 results)

  • [Journal Article] 直交配置2円柱における首飾渦挙動と表面近傍流れ2005

    • Author(s)
      山田英巳
    • Journal Title

      日本機械学会大分地方講演会講演論文集 No.058-2

      Pages: 161-162

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Effects of Necklace Vortices on Surface Flow of Two Circular Cylinders Forming a Separated Cross2005

    • Author(s)
      Hidemi YAMADA
    • Journal Title

      Proceedings of the Japan Society of Mechanical Engineers No.058-2

      Pages: 161-162

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] 直交配置された異径2円柱の間隙部に形成する首飾渦の可視化2004

    • Author(s)
      山田英巳
    • Journal Title

      可視化情報学会第32回可視化情報シンポジウム講演論文集 24-Suppl.1

      Pages: 377-378

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Visualization of Necklace Vortices between Two Cylinders Crossed with Different Diameter2004

    • Author(s)
      Hidemi YAMADA
    • Journal Title

      Journal of the Visualization Society of Japan Vol.24,Suppl.1

      Pages: 377-378

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] 十字形配置2円柱の間隙部に生成する首飾渦の可視化(渦系パターンの変化とPIV計測)2003

    • Author(s)
      山田英巳, 竹村大輔
    • Journal Title

      日本機械学会鹿児島地方講演会講演文集 No.038-2

      Pages: 111-112

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Visualization of Necklace Vortices between Two Circular Cylinders Forming a Cross (Pattern of Vortex System and PIV Measurement)2003

    • Author(s)
      Hidemi YAMADA, Daisuke TAKEMURA
    • Journal Title

      Proceedings of the Japan Society of Mechanical Engineers No.038-2

      Pages: 111-112

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 2007-12-13  

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