氾濫流に建つ直方体構造物の抗力と揚圧力:-河川自然流を用いた水理研究 その2-  [in Japanese] DRAG AND UPLIFT OF A CUBOID STRUCTURE STANDING IN INUNDATION FLOW:-Hydraulic study in natural river flow Part 2-  [in Japanese]

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Author(s)

    • 桑村 仁 KUWAMURA Hitoshi
    • 東京大学大学院工学系研究科建築学専攻 教授・Ph.D. Prof., Dept. of Architecture, School of Engineering, The University of Tokyo, Ph.D.

Abstract

 Field experiment on hydrodynamic forces exerted on a free-standing box-shaped structure partially submerged in inundation flow was conducted by using a metal frame setup on a natural riverbed wherein Froude number <i>F<sub>r</sub></i> ranged from 0.45 to 1.80. In result, following features were observed. Drag coefficient <i>C<sub>D</sub></i> is significantly affected by both the Froude number and the blockage ratio in subcritical flows in the manner that higher <i>C<sub>D</sub></i> is induced by smaller <i>F<sub>r</sub></i> as well as larger blockage, resulting in <i>C<sub>D</sub></i> varying from 0.6 to 2.1. However, their effects are negligible in supercritical flows, resulting in nearly constant <i>C<sub>D</sub></i> of 1.2±0.2, which may be attributed to reattachment of the separated flows on the side walls of the structure. Uplift coefficient <i>C<sub>upl</sub></i> is predominantly governed by <i>F<sub>r</sub></i> in a way of power law. With the elevation of <i>F<sub>r</sub></i>, the action point of uplift force shifts gradually to the upstream edge of the base of the structure, which develops a larger overturning moment.

Journal

  • Journal of Structural and Construction Engineering (Transactions of AIJ)

    Journal of Structural and Construction Engineering (Transactions of AIJ) 81(720), 219-227, 2016

    Architectural Institute of Japan

Codes

  • NII Article ID (NAID)
    130005127160
  • NII NACSIS-CAT ID (NCID)
    AN10438559
  • Text Lang
    JPN
  • ISSN
    1340-4202
  • NDL Article ID
    027097650
  • NDL Call No.
    Z16-1419
  • Data Source
    NDL  J-STAGE 
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