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

The Korean Society of Mechanical Engineers (대한기계학회)
권호 표지
DOI QR코드

DOI QR Code

Characteristics of Fluid Force Reduction for Two Different Square Prisms in a Tandem Arrangement

직렬배열에 놓인 크기가 다른 정방형주의 유체력 저감특성

  • Ro, Ki Deok (Dept. of Mechanical System Engineering.Institute of Marine Engineering, Gyeongsang Nat'l Univ.) ;
  • Kang, Chang Whan (Dept. of Mechanical System Engineering, Gyeongsang Nat'l Univ.) ;
  • Park, Kwon Ho (Dept. of Mechanical System Engineering, Gyeongsang Nat'l Univ.)
  • 노기덕 (경상대학교 기계시스템공학과.해양산업연구소) ;
  • 강창환 (경상대학교 기계시스템공학과) ;
  • 박권호 (경상대학교 기계시스템공학과)
  • Received : 2016.10.15
  • Accepted : 2017.04.10
  • Published : 2017.07.01
Download PDF
⟨ Previous Next ⟩

Abstract

The Characteristics of the flowfields of a square prism having a small square prism were investigated by measuring of lift and drag on the square prism and visualizing the flowfield using PIV. The experimental parameters were the width ratios(H/B=0.2~0.6) of small square prisms to the prism width and the gap ratios (G/B=0~3) between the prism and the small square prism. The drag reduction rate of the square prism initially increased and then decreased with the G/B ratio for the same H/B ratio, and increased with the H/B ratio for the same G/B ratio. The maximum drag reduction rate of 98.0% was observed at H/B=0.6 and G/B=1.0. The lift reduction rate of the square prism was not affected by the width and gap ratios; the total average value was approximately 66.5%. In case of a square prism having a small square prism, the stagnation regions were represented in the upstream and downstream sides of the square prism.

본 연구는 고 레이놀즈 영역에서 상류측에 작은 정방형주(Square prism)를 가진 정방형주의 유동장 특성을 양 항력측정 실험과 PIV를 이용한 가시화 실험으로 파악한 것이다. 실험변수는 정방형주 한변의 길이에 대한 작은 정방형주의 폭비(H/B=0.2~0.6) 및 정방형주 전면에서부터 작은 정방형주의 후면 까지의 거리(G/B=0~3)로 했다. 작은 정방형주의 폭비를 고정시킨 경우 정방형주의 항력감소율은 간격비가 증가할수록 증가하다 감소하는 특성을 보였다. 또한 같은 간격비에서는 작은 정방형주의 폭비가 클수록 정방형주의 항력감소율이 컸다. 또한 같은 간격비에서는 작은 정방형주의 폭비가 클수록 정방형주의 항력감소율이 증가했으며, 폭비 H/B=0.6, 간격비 G/B=1.0일 때 최대 98.0%의 항력감소율을 보였다. 정방형주의 양력감소율은 작은 정방형주의 폭비 및 간격비에 거의 영향을 받지 않았으며, 양력감소율의 전체 평균치는 66.5% 정도였다. 작은 정방형주를 설치한 경우 정방형주 상류측과 하류측에 정체영역이 나타났다.

Keywords

References

  1. Khalighi, B., Zang S., Korokilas, C. and Balkanyi, S. R., 2001, "Experimental and Computational Study of Unsteady Wake Flow Behind a Bluff Body with a drag Reduction Device," Society of Automotive Engineers, 2001-01-1042.
  2. Tamura, T. and Miyagi, T., 1999, "The Effect of Turbulence on Aerodynamic Forces on a Square Cylinder with Various Corner Shapes," Journal of Wind Engineering and Industrial Aerodynamics, Vol. 83, pp. 135-145. https://doi.org/10.1016/S0167-6105(99)00067-7
  3. Ro, K. D. and Kim, K. S., 2006, "Fluid Force Reduction Characteristics of a Square Prism Having Fences on the Corner," Journal of the Korean Society of Marine Engineering, Vol. 30, No. 3, pp. 389-395.
  4. Ro, K. D., Kim, K. S. and Oh, S. K., 2008, "The Visualization of the Flowfield Around Square Prism Having Fences Using the PIV," Journal of The Korean Society of Marine Engineering, Vol. 32, No. 1, pp. 94-99. https://doi.org/10.5916/jkosme.2008.32.1.94
  5. Park, W. C., 1993, "Effect of the Length of a Splitter Plate on Drag Reduction," Trans. Korean Soc. Mech. Eng. B, Vol. 17, No. 11, pp. 2809-2815.
  6. Doolan, C. J., 2009, "Flat-Plate Interaction with the Near Wake of a Square Cylinder," The American Institute of Aeronautics and Astronautics Journal, Vol. 47, No. 2, pp. 475-478. https://doi.org/10.2514/1.40503
  7. Ro, K. D., 2014, "Experimental Characterization of the Flow Field of Square Prism with a Detached Splitter Plate at High Reynolds Number," Journal of Mechanical Science and Technology, Vol. 28, No. 7, pp. 2651-2657. https://doi.org/10.1007/s12206-014-0621-5
  8. Ro, K. D., 2013, "Characteristic Calculation of Flowfield Around a Square Prism Having a Detached Splitter Plate using Vortex Method," Journal of the Korean Society of Marine Engineering, Vol. 37, No. 2, pp. 156-162. https://doi.org/10.5916/jkosme.2013.37.2.156
  9. Igarashi, T., 1997, "Drag Reduction of a Square Prism by Flow Control using a Small Rod," Journal of Wind Engineering and Industrial Aerodynamics, Vol. 69, No. 71, pp. 141-153.
  10. Sakamoto, H., Tan, K., Takeuchi, N. and Haniu, H., 1997, "Suppression of Fluid Forces Actiong on a Square Prism by Passive Control," Journal of Fluids Engineering, Vol. 119, pp. 506-511. https://doi.org/10.1115/1.2819273
  11. Igarashi, T., 1997, "Drag Reduction of a Square Prism by Flow Control using a Small Rod," Journal of Wind Engineering and Industrial Aerodynamics, Vol. 69, No. 71, pp. 141-153.
  12. Sakamoto, H., Tan, K., Takeuchi, N. and Haniu, H., 1997, "Suppression of Fluid Forces Acting on a Square Prism by Passive Control," Journal of Fluids Engineering, Vol. 119, pp. 506-511. https://doi.org/10.1115/1.2819273
  13. Zhou, L., Cheng, M. and Hung, K. C., 2005, "Suppression of Fluid Force on a Square Cylinder by Flow Control," Journal of Fluids and Structures, Vol. 21, pp. 151-167. https://doi.org/10.1016/j.jfluidstructs.2005.07.002
  14. Ro, K. D., 2015, "Experimental Characterization of Flow Field Around a Square Prism with a Small Triangular Prism," Journal of Mechanical Science and Technology, Vol. 29, No. 4, pp. 1649-1656. https://doi.org/10.1007/s12206-015-0336-2