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

The Korean Society of Mechanical Engineers (대한기계학회)
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Characteristics of Flowfield of a Circular Cylinder Having a Detached Splitter Plate with High Reynolds Number

고 레이놀즈 수에서 분리된 분할판을 가진 원주의 유동장 특성

  • Ro, Ki Deok (Dept. of Mechanical System Engineering & Institute of Marine Engineering, Gyeongsang Nat'l Univ.) ;
  • Lee, Han Gyun (Dept. of Mechanical System Engineering, Gyeongsang Nat'l Univ.) ;
  • Lee, Jong Ho (Dept. of Mechanical System Engineering, Gyeongsang Nat'l Univ.) ;
  • Lee, Jeong Min (Dept. of Mechanical System Engineering, Gyeongsang Nat'l Univ.) ;
  • Shin, Jin Ho (Dept. of Mechanical System Engineering, Gyeongsang Nat'l Univ.) ;
  • Cheon, Kang Bin (Dept. of Mechanical System Engineering, Gyeongsang Nat'l Univ.)
  • 노기덕 (경상대학교 기계시스템공학과.해양산업연구소) ;
  • 이한균 (경상대학교 기계시스템공학과) ;
  • 이종호 (경상대학교 기계시스템공학과) ;
  • 이정민 (경상대학교 기계시스템공학과) ;
  • 신진호 (경상대학교 기계시스템공학과) ;
  • 천강빈 (경상대학교 기계시스템공학과)
  • Received : 2015.12.17
  • Accepted : 2016.03.02
  • Published : 2016.06.01
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Abstract

In this study, we investigate the characteristics of the drag reduction of a circular cylinder having a detached splitter plate at the wake side. We measure the fluid force on a circular cylinder and visualize the field using particle image velocimetry (PIV) with a high Reynolds number, Re = 10,000. The experimental paraeters used were the width ratios (H/B = 0.5~1.5) of splitters to the prism width and the gap ratios (G/B = 0~2) between the prism and the splitter plate. The drag-reduction rate of the circular cylinder increased with H/B in the case of the same G/B, and it increased and then decreased with G/B in the case of the same H/B. The vortices of the opposite direction on the upper and lower sides of the detached splitter plate were generated by installing the plate. Reverse flow was caused by the vortices at the wake region of the circular cylinder, and the drag of the circular cylinder was decreased by the reverse flow.

본 연구는 고 레이놀즈 영역에서 후류측에 분리된 분할판(Detached splitter plate)을 가진 원주의 유동장 특성을 양 항력측정 실험과 PIV를 이용한 가시화 실험으로 파악한 것이다. 실험파라메터는 원주 한변의 길이에 대한 분할판의 폭비(H/B=0.5~1.5) 및 원주 후면에서부터 분할판의 앞전까지의 거리(G/B=0~2)로 했다. 분할판의 폭비를 고정시킨 경우 원주의 항력감소율은 간격비가 증가할수록 증가한 후 감소하는 특성을 보였다. 또한 같은 간격비에서는 분할판의 폭비가 클수록 원주의 항력감소율이 컸다. 분리된 분할판의 설치에 의해 분할판의 상, 하부에는 서로 반대방향의 볼테스가 발생되었고, 이 볼텍스가 원주 후류측에 역류를 발생시켜, 원주에 작용하는 항력을 감소시켰다.

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References

  1. Gad-el-Hak, M., 1996, "Modern Developments in Flow Control," Applied Mechanics Reviews, Vol. 49, No.7, pp. 365-379 https://doi.org/10.1115/1.3101931
  2. Achenbach, E., 1971, "Influence of Surface Roughness on the Cross-Flow Around a Circular Cylinder," Journal of Fluid Mechanics, Vol. 46, No. 2, pp. 321-335. https://doi.org/10.1017/S0022112071000569
  3. Guven, O., Farell, C. and Patel, V. C., 1980, "Surface Roughness Effects on the Mean Flow past Circular Cylinders," Journal of Fluid Mechanics, Vol. 98, No. 4, pp. 673-701. https://doi.org/10.1017/S0022112080000341
  4. Lim, H. C. and Lee, S. J., 2001, "An Experimental Study on Drag Reduction of Grooved Cylinders," Trans. Korean Soc. Mech. Eng. B, Vol. 25, No. 2, pp. 260-268. https://doi.org/10.22634/KSME-B.2001.25.2.260
  5. Aoki, K., Lee, S. and Oki, M., 1998, "Drag and Flow Characteristics Around the Circular Cylinder with Grooves." Trans(B). of the Japan Society of Mechanical Engineers, Vol. 64, No. 617, pp. 18-24. https://doi.org/10.1299/kikaib.64.18
  6. Ro, K. D., 2001, "Drag Reduction of Cylinder with Dimpled Surface," Journal of the Korean Society of Marine Engineers, Vol. 25, No. 1, pp. 155-161.
  7. Ro, K. D. and Park, J. T., 2002, "Drag Reduction Characteristics of Cylinder Having Square Dimpled Surface," Journal of the Korean Society of Marine Engineers, Vol. 26, No. 3, pp. 233-239.
  8. Anderson, E. A. and Szewczyk, A. A., 1997, "Effects of a Splitter Plate on the Near Wake of a Circular Cylinder in 2 and 3-dimensional Flow Configurations," Experiments in Fluids, Vol. 23, pp. 161-174. https://doi.org/10.1007/s003480050098
  9. Wu, J., Shu, C. and Zhao, N., 2014, "Investigation of Flow Characteristics Around a Stationary Circular Cylinder with an Undulatory Plate," European Journal of Mechanics B/Fluids Vol. 48, pp. 27-39. https://doi.org/10.1016/j.euromechflu.2014.04.007
  10. Sun, S. H., Hwang, J. Y. and Yang, K. S., 2001, "Drag Reduction on a Circular Cylinder using a Detached Splitter Plate," Trans. Korean Soc. Mech. Eng. B, Vol. 25, No. 11, pp. 1632-1639. https://doi.org/10.22634/KSME-B.2001.25.11.1632