Transactions of the Korean Society of Mechanical Engineers B (대한기계학회논문집B)

The Korean Society of Mechanical Engineers (대한기계학회)
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Characteristics of Near Wake Behind a Circular Cylinder with Serrated fins (IV) - Comparison of Vortex Formation Regions -

톱니형 휜이 부착된 원주의 근접후류특성 연구 (IV) - 와형성영역의 유동비교 -

  • 류병남 (부산대학교 대학원 기계공학과) ;
  • 김경천 (부산대학교 기계공학부, 기계기술연구소) ;
  • 부정숙 (부산대학교 기계공학부, 기계기술연구소)
  • Published : 2003.03.01
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Abstract

An experimental study is performed to investigate characteristics of near of wakes of circular cylinders with serrated fins using a hot-wire anemometer for various freestream velocities. The main focus of this paper is to investigate a reason why a vortex formation length is increased suddenly. Velocity of the fluid which flow through fins decreases as fin's height and freestream velocity increases and fin pitch decreases, and a thickness of boundary layer increases. The finned tube has a lower velocity gradient when the higher boundary layer grows. This velocity gradient on finned tube makes a weak shear force in the wake and moves to downstream in a state of lower momentum transfer between the freestream and the wake. The phenomenon makes a vortex formation length increased suddenly. The fluctuations of the velocity distributions on the finned tube and (equation omitted) = 1.0 contour line in the vortex formation region decreases when the fin height increases and the pitch decreases.

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References

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