Hostname: page-component-745bb68f8f-grxwn Total loading time: 0 Render date: 2025-01-25T22:33:18.822Z Has data issue: false hasContentIssue false
  • English
  • Français

Effects of Flow Patterns on Aerodynamic Forces of a Square Cylinder at Incidence

Published online by Cambridge University Press:  31 August 2011

R. F. Huang  and
B. H. Lin
R. F. Huang*
Affiliation:
Department of Mechanical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan 10607, R.O.C.
B. H. Lin
Affiliation:
Department of Mechanical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan 10607, R.O.C.
*
*Professor, corresponding author
Get access

Abstract

The pressure distributions around a square cylinder in a crossflow were experimentally studied in a wind tunnel. The subject of study was conventional, but the results presented new findings. The experiments were performed by using a home-made linear pressure scanner. The ranges of Reynolds number and incidence angle were 2 × 104 - 9.4 × 104 and 0° - 45°, respectively. According to the topological flow patterns, the flows around the square cylinder at incidence showed three characteristic regimes: The subcritical, supercritical, and wedge flows. A critical incidence angle αcri = 15° separated the regimes of subcritical and supercritical modes. The results of current study provided information regarding the effects of the topological flow patterns on surface pressure distribution, drag, and lift characteristics. The pressure distributions, drag, and lift presented different characteristics in different characteristic flow regimes and had close correlations with the flows. At the critical incidence angle 15° which separated the subcritical and supercritical regimes, the surface-averaged pressure coefficient on each face displayed local extreme value—The drag coefficient attained a minimum of 1.6, the lateral force coefficient reached a maximum of 0.9. The appearance of the minimum drag at the critical incidence angle was attributed to the reduction of wake width which was induced by two surface flow phenomena: (1) reattachment of the separated boundary layer on the lateral surface facing windward at the critical incidence angle and (2) flow pattern change on the lateral surface facing leeward.

Keywords

Square cylinderPressure distributionDrag and lift
Type
Articles
Information
Journal of Mechanics , Volume 27 , Issue 3 , September 2011 , pp. 347 - 355
Copyright
Copyright © The Society of Theoretical and Applied Mechanics, R.O.C. 2011

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Zdravkovich, M. M., Flow around Circular Cylinder. Oxford University Press, Oxford, UK, pp. 1–117 (1997).CrossRefGoogle Scholar
2. Okajima, A., “Strouhal Numbers of Rectangular Cylinders,” Journal of Fluid Mechanics, 123, pp. 379–398 (1982).CrossRefGoogle Scholar
3. Igarashi, T., “Characteristics of the Flow around a Square Prism,” Bulletin of JSME, 27, pp. 1858–1865 (1985).CrossRefGoogle Scholar
4. Lee, B. E., “The Effect of Turbulence on the Surface Pressure Field of a Square Prism,” Journal of Fluid Mechanics, 69, pp. 321–352 (1975).CrossRefGoogle Scholar
5. Obasaju, E. D., “An Investigation of the Effects of Incidence on the Flow around a Square Section Cylinder,” Aeronautical Quarterly, 34, pp. 243–259 (1983).CrossRefGoogle Scholar
6. Rockwell, D. O., “Organized Fluctuations due to Flow Past a Square Cross Section Cylinder,” Journal of Fluids Engineering, 99, pp. 511–516 (1977).CrossRefGoogle Scholar
7. Noberg, C., “Flow around Rectangular Cylinders: Pressure Forces and Wake Fequencies,” Journal of Wind Engineering and Industrial Aerodynamics, 49, pp. 187–196 (1993).CrossRefGoogle Scholar
8. Dutta, S., Muralidhar, K. and Panigrahi, P. K., “Influence of the Orientation of a Square Cylinder on the Wake Properties,” Experiments in Fluids, 34, pp. 16–23 (2003).CrossRefGoogle Scholar
9. Sarioglu, M., Akansu, Y. E. and Yavuz, T., “Control of Flow Around Aquare Cylinders at Incidence by Using a Rod,” AIAA Journal, 43, pp. 1419–1426 (2005).CrossRefGoogle Scholar
10. Vickery, B. J., “Fluctuating lift and Drag on a Long Cylinder of Square Cross-Section in a Smooth and in a Turbulent Stream,” Journal of Fluid Mechanics, 25, pp. 481–494 (1966).CrossRefGoogle Scholar
11. Bearman, P.W. and Trueman, D. M., “An Investigation of the Flow around Rectangular Cylinders,” Aeronautical Quarterly, 23, pp. 229–237 (1972).CrossRefGoogle Scholar
12. Rockwell, D. O., “Organized Fluctuations Due to Flow Past a Square Cross-Section Cylinder.” Journal of Fluids Engineering, 99, pp. 511–516 (1977).CrossRefGoogle Scholar
13. Chen, J. M. and Liu, C.-H., “Vortex Shedding and Surface Pressures on a Square Cylinder at Incidence to a Uniform Air Stream,” International Journal of Heat and Fluid Flow, 20, pp. 592–597 (1999).CrossRefGoogle Scholar
14. Duräo, D. F. G., Heitor, M. V. and Pereira, J. C. F., “Measurements of Turbulent and Periodic Flows around a Square Cross-section Cylinder,” Experiments in Fluids, 6, pp. 298–304 (1988).CrossRefGoogle Scholar
15. Lyn, D. A., Einav, S., Rodi, W. and Park, J.-H., “A Laser-Doppler Velocimetry Study of Ensemble- averaged Characteristics of the Turbulent near Wake of a Square Cylinder,” Journal of Fluid Mechanics, 304, pp. 285–319 (1995).CrossRefGoogle Scholar
16. Kurtulus, D. F., Scarano, F. and David, L., “Unsteady Aerodynamic Forces Estimation on a Square Cylinder by TR-PIV,” Experiments in Fluids, 42, pp. 185–196 (2007).CrossRefGoogle Scholar
17. Van Oudheusden, B. W., Scarano, F., Van Hinsberg, N. P. and Watt, D. W., “Phase-resolved Characterization of Vortex Shedding in the near Wake of a Square-Section Cylinder at Incidence,” Experiments in Fluids, 39, pp. 86–98 (2005).CrossRefGoogle Scholar
18. Huang, R. F., Lin, B. H. and Yen, S. C., “Time-Averaged Topological Flow Patterns and Their Influence on Vortex Shedding of a Square Cylinder in Crossflow at Incidence” Journal of Fluids and Structures, 26, pp. 406–429 (2010).CrossRefGoogle Scholar
19. West, G. S. and Apelt, C. J., “The Effects of Tunnel Blockage and Aspect Ratio on the Mean Flow past a Circular Cylinder with Reynolds Number Between 104 and 105,” Journal of Fluid Mechanics, 114, pp. 361–377 (1982).CrossRefGoogle Scholar
20. Stansby, P. K., “The Effects of End Plates on the Base Pressure Coefficient of a Circular Cylinder,” Aeronautical Journal, 78, pp. 36–37 (1974).CrossRefGoogle Scholar
21. Fox, T. A. and West, G. S., “On the Use of End Plates with Circular Cylinders,” Experiments in Fluids, 9, pp. 237–239 (1990).CrossRefGoogle Scholar
22. Gerich, D. and Eckelmann, H., “Influence of End Plates and Free Ends on the Shedding Frequency of Circular Cylinders,” Journal of Fluid Mechanics, 122, pp. 109–121 (1982).CrossRefGoogle Scholar
23. Tamura, T. and Miyagi, T., “The Effect of Turbulence on Aerodynamic Forces on a Square Cylinder with Various Corner Shapes,” Journal of Wind Engineering and Industrial Aerodynamics, 83, pp. 135–145 (1999).CrossRefGoogle Scholar