Wind and Structures

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Advancing drag crisis of a sphere via the manipulation of integral length scale

  • Moradian, Niloofar (Department of Mechanical, Automotive and Materials Engineering, University of Windsor) ;
  • Ting, David S.K. (Department of Mechanical, Automotive and Materials Engineering, University of Windsor) ;
  • Cheng, Shaohong (Department of Civil and Environmental Engineering, University of Windsor)
  • Received : 2009.07.16
  • Accepted : 2010.05.19
  • Published : 2011.01.25
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Abstract

Spherical object in wind is a common scenario in daily life and engineering practice. The main challenge in understanding the aerodynamics in turbulent wind lies in the multi-aspect of turbulence. This paper presents a wind tunnel study, which focuses on the role of turbulence integral length scale ${\Lambda}$ on the drag of a sphere. Particular turbulent flow conditions were achieved via the proper combination of wind speed, orifice perforated plate, sphere diameter (D) and distance downstream from the plate. The drag was measured in turbulent flow with $2.2{\times}10^4{\leq}Re{\leq}8{\times}10^4$, $0.043{\leq}{\Lambda}/D{\leq}3.24$, and turbulence intensity Tu up to 6.3%. Our results confirmed the general trends of decreasing drag coefficient and critical Reynolds number with increasing turbulence intensity. More interestingly, the unique role of the relative integral length scale has been revealed. Over the range of conditions studied, an integral length of approximately 65% the sphere diameter is most effective in reducing the drag.

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References

  1. Achenbach, E. (1972), "Experiments on the flow past spheres at very high Reynolds numbers", J. Fluid Mech., 54(3), 565-575. https://doi.org/10.1017/S0022112072000874
  2. Ahlborn, F. (1931), "Turbulence and mechanism of resistance to flow by spheres and cylinders", J. Tech. Phys., 12(10), 482-488.
  3. Anderson, T.J. and Uhlherr, P.H.T. (1977), "The influence of stream turbulence on the drag of freely entrained spheres", Proceedings of the 6th Australasian Hydraulics and Fluid Mechanics Conference, Adelaide, SA, Australia, December.
  4. Bakic, V. and Peric, M. (2005), "Visualization of flow around sphere for Reynolds numbers between 22000 and 400000", Thermophys. Aeromech., 12(3), 307-315.
  5. Batchelor, G.K. (1967), An Introduction to Fluid Dynamics, Cambridge University Press, USA.
  6. Brownlee, K.A. (1960), Statistical Theory and Methodology in Science and Engineering, John Wi1ey, New York.
  7. Cengel, Y.A. and Cimbala, J.M. (2006), Fluid Mechanics: Fundamentals and Applications, McGraw-Hill Science.
  8. Clamen, A. and Gauvin, W.H. (1969), "Effects of turbulence on the drag coefficients of spheres in a supercritical flow regime", AICHE J., 15(2), 184-189. https://doi.org/10.1002/aic.690150211
  9. Clift, R. and Gauvin, W.H. (1970), "The motion of particles in turbulent gas streams", Proceedings of the Chemeca '70: A Conference convened by the Australian National Committee of the Institution of Chemical Engineers and the Australian Academy of Science, Melbourne and Sydney, Australia, August.
  10. Clift, R. and Gauvin, W.H. (1971), "Motion of entrained particles in gas streams, Can. J. Chem. Eng., 49(4), 439-448. https://doi.org/10.1002/cjce.5450490403
  11. Czichos, H., Saito, T. and Smith, L. (2006), Springer Handbook of Materials Measurement Methods, Springer Berlin Heidelberg.
  12. Dryden, H.L. and Kuethe, A.M. (1930), Effect of turbulence in wind tunnel measurements, National Advisory Committee for Aeronautics, Report No. 342.
  13. Dryden, H.L., Schubauer, G.B., Mock, W.C. and Bkrambtad, H.K. (1937), Measurements of intensity and scale of wind-tunnel turbulence and their relation to the critical Reynolds number of spheres, National Advisory Committee for Aeronautics, Report No. 581.
  14. Lamb, H. (1945), Hydrodynamics, 6th Ed., Dover Publications, New York.
  15. Liu, R. and Ting, D.S.K. (2007), "Turbulent flow downstream of a perforated plate: Sharp-edged orifice versus finite-thickness holes", J. Fluid. Eng.-T. ASME, 129(9), 1164-1171. https://doi.org/10.1115/1.2754314
  16. Liu, R., Ting, D.S.K. and Checkel, M.D. (2007), "Constant Reynolds number turbulence downstream of an orificed, perforated plate", Exp. Therm. Fluid Sci., 31(8), 897-908. https://doi.org/10.1016/j.expthermflusci.2006.09.007
  17. Mohd-Yusof, J. (1996), Interaction of massive particles with turbulence, PhD Thesis, Department of Mechanical Engineering, Cornell University.
  18. Moradian, N. (2008), The effects of freestream turbulence on the drag of a sphere, MASc Thesis, University of Windsor.
  19. Moradian, N., Ting, D.S.K. and Cheng, S. (2009), "The effects of freestream turbulence on the drag coefficient of a sphere", Exp. Therm. Fluid Sci., 33(3), 460-471. https://doi.org/10.1016/j.expthermflusci.2008.11.001
  20. Neve, R.S. (1986), "The importance of turbulence macroscale in determining the drag coefficient of spheres", Int. J. Heat Fluid Fl., 7(1), 28-36 https://doi.org/10.1016/0142-727X(86)90040-8
  21. Neve, R.S. and Shansonga, T. (1989), "The effects of turbulence characteristics on sphere drag", Int. J. Heat Fluid Fl., 10(4), 318-321. https://doi.org/10.1016/0142-727X(89)90020-9
  22. Prandtl, L. (1914), Der luftwmiderstand von kugeln, Nachrichten von der Konigliche Gesellschaft der Wissenschaften zu Gottingen, Mathematisch-Physikalische Klasse, 177-190.
  23. Sankagiri, S. and Ruff, G.A. (1997), "Measurement of sphere drag in high turbulent intensity flows", Proceedings of the ASME Fluids Engineering Division Summer Meeting (FEDSM'97), Vancouver, Canada, June.
  24. Schlichting, H. (1955), "Berechnung der reibungslosen, inkompressiblen Strömung für ein vorgegebenes ebenes Schaufelgitter", Verein Deutscher Ingenieure -- VDI Zeitschrift, No. 447, 269-270.
  25. Schlichting, H. (1979), Boundary Layer Theory, McGraw-Hill.
  26. Shepherd, C.B. and Lapple, C.E. (1940), "Flow pattern and pressure drop in cyclone dust collectors", J. Ind. Eng. Chem., 32, 1246-1248. https://doi.org/10.1021/ie50369a042
  27. Speziale, C.G. and Bernard, P.S. (1992), "The energy decay in self-preserving isotropic turbulence revisited", J. Fluid Mech., 241, 645-667. https://doi.org/10.1017/S0022112092002180
  28. Taylor, G.I. (1938), "The spectrum of turbulence", Proc. Roy. Soc. A-Math Phy., 164, 476-490. https://doi.org/10.1098/rspa.1938.0032
  29. Torobin, L.B. and Gauvin, W.H. (1959), "Fundamental aspects of solids-gas flow, Part II: the sphere wake in steady laminar fluids", Can. J. Chem. Eng., 37, 167-176. https://doi.org/10.1002/cjce.5450370501
  30. Torobin, L.B. and Gauvin, W.H. (1960), "Fundamental aspects of solids-gas flow, Part V: the effects of fluid turbulence on the particle drag coefficient", Can. J. Chem. Eng., 38, 189-200. https://doi.org/10.1002/cjce.5450380604
  31. Torobin, L.B. and Gauvin, W.H. (1961), "The drag coefficients of single spheres moving in a steady and accelerated motion in a turbulent fluid", AICHE J., 7(4), 615-619. https://doi.org/10.1002/aic.690070417
  32. Zarin, N.A. (1970), Measurement of non-continuum and turbulence effects on subsonic sphere drag, NASA Report, NCR-1585.
  33. Zarin, N.A. and Nicholls, J.A. (1971), "Sphere drag in solid rocket--non-continuum and turbulence effects", Combust. Sci. Techol., 3(6), 273-285. https://doi.org/10.1080/00102207108952295

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