자유수면에 접한 원형실린더 주위의 유동계측

Flow Characteristics around a Circular Cylinder according as the Depth from Free Surface

  • Shon, Chang-Bae (Division of Ocean Engineering, Korea Maritime University) ;
  • Gim, Ok-Sok (Mokpo National Maritime University) ;
  • Oh, Woo-Jun (Graduate School of Mokpo National Maritime University) ;
  • Lee, Chang-Woo (Graduate School of Mokpo National Maritime University) ;
  • Lee, Gyoung-Woo (Division of Ocean System Engineering, Mokpo National Maritime University)
  • 발행 : 2010.04.22

초록

자유수면에 접한 원형실린더는 후류유동에 변화를 초래한다. 이를 위해 희류수조의 수면하 깊이를 변화시키며 $Re=1.0\times10^3$에서 순간유동장을 계측하여 실험을 통하여 그 영향을 조사하였다. 계측된 결과는 상호상관 PIV기법을 이용하여 원형실린더의 2차원 유동특성을 알아보기 위하여 상호 비교하였다. 자유수면에 의한 원형실린더 주변유동은 후류에 영향을 미친다. 특히 d=l.0D의 경우에 있어서 경계층은 전체 영역에 걸쳐 분포하였다. 원형실린더의 박리점과 경계층은 수심의 깊이에 따라 제어가 가능하였다.

The Free surface influenced the wake behind a circular cylinder and its effects were investigated experimentally in a circulating water channe with the variation of water depth Instantaneous velocity fields were measured in this paper. the measured results has been compared with each other to investigate the flow characteristics of the circular cylinder's 2-dimensional section at $Re=1.0\times10^3$ using 2-frame grey level cross correlation PIV method. The flow around the circular cylinder with free surface affected the wake structure. especially, in case of d=1.0D, the boundary layer was measured in the whole area. The separation point and boundary layer of the circular cylinder could be controlled by the water depth.

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