Effect of Boundary Layer Thickness on the Flow Around a Rectangular Prism

직사각형 프리즘 주위의 유동구조에 대한 경계층 두께의 영향

  • 지호성 (부산대학교 기계공학부 기계기술연구소) ;
  • 김경천 (부산테크노파크 부산대부소 연구원) ;
  • 이승홍 (부산대학교 기계공학부) ;
  • 부정숙 (부산대학교 기계공학부)
  • Published : 2002.06.01


Effect of boundary layer thickness on the flow characteristics around a rectangular prism has been investigated by using a PIV(Particle Image Velocimetry) technique. Three different boundary layers(thick, medium and thin)were generated in the Atmospheric Boundary Layer Wind Tunnel at Pusan National University. The thick boundary layer having 670 mm thickness was generated by using spires and roughness elements. The medium thickness of boundary layer($\delta$=270 mm) was the natural turbulent boundary layer at the test section floor with fairly long developing length(18 m). The thin boundary layer($\delta$=36.5 mm) was generated on the smooth panel elevated 70cm from the wind tunnel floor. The Reynolds number based on the free stream velocity(3 ㎧) and the height of the model(40 mm) was 7.9$\times$10$^3$. The mean velocity vector fields and turbulent kinetic energy distributions were measured and compared. The effect of boundary layer thickness was clearly observed not only in the length of separation bubble but also in the location of reattachment point. The thinner the boundary layer thickness, the higher the turbulent kinetic energy Peak around the model roofbecame. It is strongly recommended that the height ratio between the model and the approaching boundary layer thickness should be encountered as a major parameter.



  1. Hosker, R. P. Jr., 1984, 'Flow and Diffusion Near Obstacles, in Darry Randerson(Eds.),' Atmospheric Science and Power Production, DOE/TIC-27601, U.S. Department of Energy
  2. Akins, R. E. and Reinhold, T. A., 1998, 'Laser Doppler Velocimeter Measurements of Separated Shear Layer on Bluff Bodies,' J. Wind & Eng. Ind. Aereodyn. Vol. 74-76, pp. 455-461
  3. Banks, D., Meroney, R. N., Sarkar, P. P., Zhao, Z. and Wu, F., 2000, 'Flow Visualization of Condical Vortices on Flat Roofs with Simutaneous Surface Pressure Measurement,' J. Wind. Eng. & Ind. Aerodyn Vol. 84, pp. 65-84
  4. Ham, H. J. and Bienkiewicz, B., 1998, 'Wind Tunnel Simulation of TTU Flow and Building Roof Pressure,' J. Wind Eng. & Ind. Aerodyn Vol. 77&78, pp. 119-133
  5. Cheung, J. C. K., Holmes, J. D., elbourne, W. H., Lakshmanan, N. and Bowditch, P., 1997, 'Pressure on a 1/10 Scale Model of the Texas Tech building,' J. Wind Eng. & Ind. Aerodyn. Vol. 69-71, pp. 529-538
  6. Poitras, G., Brizzi, L. E., Pecheux, J. and Gagnon, Y., 2000, 'The Study of Fluid Flows in the Immediate Vicinity of Building Models,' 9th Int. Symp. on Flow Visualization, pp. 246-1-246-10
  7. 김경천, 지호성, 성승학, 2001, '직사각형 프리즘 상면에서 발생하는 원추형 와의 유동구조,' 대한기계학회논문집 B권, 제25권, 제5호, pp. 713-721
  8. 지호성, 김경천, 추재민, 이석호, 성승학, 2001, '두꺼운 난류경계층 내부에 놓인 직사각형 프리즘 주위의 유동구조,' 대한기계학회논문집 B권, 제26권, 제4호, pp. 548-586
  9. Melling, A., 1997, 'Tracer Particles and Seeding for Particle Image Velocimetry,' Meas. Sci & Technol. Vol. 8, pp. 1406-1416
  10. Soloff, S. M., Adrian, R. J. and Liu, Z. C., 1997, 'Distortion Compensation for Generalized Stereoscopic Particle Image Velocimetry,' Meas. Sci. & Technol. Vol. 8, pp. 1441-1454