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 (III) - Mechanism of Velocity Recovery -

톱니형 휜이 부착된 원주의 근접후류특성 연구 (III) - 속도회복 메카니즘에 관하여 -

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

The characteristics of near wakes of circular cylinders with serrated fins are investigated experimentally using a hot-wire anemometer for various freestream velocities. Near wake structures of the fin tubes are observed using a phase average technique. With increasing fin height and decreasing fin pitch. oscillation of streamwise velocity increases. It file oscillation of lateral velocity decreases. The time averaged V-component velocity distribution of the finned tube is contrary to that of the circular cylinder due to the different strength of entrainment flow. This strength is affected by the distance of (equation omitted) = 1.0 contour lines. (equation omitted) = 1.0 contour line approaches to the wake center line when the fin density is increased. When the distance between (equation omitted) = 1.0 contour lines comes close the shear force should be increased and the flow toward the wake center line can be more strengthened because of the shear force. Factors related to the velocity recovery in the near wake of the finned tube are attributed to tile turbulent intensity, the boundary layer thickness. the position and strength of entrainment process.

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References

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