Journal of Advanced Marine Engineering and Technology

The Korean Society of Marine Engineering (한국마린엔지니어링학회)
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Experiments on the flow field of a circular cylinder having a front vertical plate

정면에 수직평판을 가진 원주의 유동장 특성실험

  • Ro, Ki-Deok (Department of Mechanical System Engineering.Institute of Marine Engineering, Gyeongsang National University)
  • Received : 2015.07.20
  • Accepted : 2015.10.27
  • Published : 2016.03.31
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Abstract

The characteristics of the flow field of a circular cylinder having a small vertical plate at the upstream side are investigated by measuring the fluid force on the circular cylinder and by visualizing the flow field using particle image velocimetry. The experimental parameters are the width ratios (H/B = 0.2-0.6) of the vertical plates to the circular cylinder's diameter, and the gap ratios (G/B = 0-3) between the circular cylinder and the vertical plate. The drag reduction rate and Strouhal number of the circular cylinder increased and then decreased with G/B in the case of the same H/B. The drag reduction rate increased with H/B in the case of the same G/B. In the case of a circular cylinder having a small vertical plate, the stagnation regions are represented on the upstream and downstream sides of the circular cylinder, and the size of that region on the upstream side increased with H/B.

본 연구는 상류측에 작은 수직평판를 가진 원주의 유동장 특성을 양 항력측정 실험과 PIV를 이용한 가시화 실험으로 파악한 것이다. 실험 파라메터는 원주의 직경에 대한 수직평판의 폭비(H/B = 0.2~0.6) 및 원주의 앞면 중심에서부터 수직평판까지의 거리(G/B = 0~3)로 했다. 수직평판의 폭비를 고정시킨 경우 원주의 항력감소율은 간격비가 증가할수록 증가하다 감소하는 특성을 보였다. 또한 같은 간격비에서는 수직평판의 폭비가 클수록 원주의 항력감소율이 컸다. 원주의 Strouhal 수는 간격비가 증가할수록 증가하다 감소하는 특성을 보였다. 수직평판을 설치한 경우 원주 상류측과 하류측에 정체영역이 나타났으며, 그 크기는 상류측은 수직평판의 폭비가 클수록 증가하는데 비해, 하류측은 거의 일정했다.

Keywords

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