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Experiments in Fluids

, 56:82 | Cite as

Three-dimensional flow structure along simultaneously pitching and rotating wings: effect of pitch rate

  • M. Bross
  • D. Rockwell
Research Article

Abstract

The flow structure along a simultaneously pitching and rotating wing is investigated using quantitative flow visualization. Imaging is performed for a range of pitch rates, with emphasis on the three-dimensional structure during start-up and relaxation. Surfaces of transparent iso-Q and helicity are employed to interpret the flow physics. The onset and development of the components of the vortex system, i.e., the leading-edge, tip, and trailing-edge vortices, are strongly influenced by the value of pitch rate relative to the rotation rate. Comparisons at the same angle of attack indicate that the formation of vortical structures is delayed with increasing pitch rate. However, comparisons at the same rotation angle for different values of pitch rate reveal similar flow structures, thereby indicating predominance of rotation effects. Extreme values of pitch rate can lead to radically different sequences of development of the components of the three-dimensional vortex system. Nevertheless, consistently positive vorticity flux is maintained through these components and the coherence of the vortex system is maintained.

Keywords

Vortex Flow Structure Vortical Structure Vortex System Pitch Rate 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notes

Acknowledgments

The authors are pleased to acknowledge the financial support of the Air Force Office of Scientific Research under Grant No. FA9550-11-1-0069 monitored by Dr. Douglas Smith.

References

  1. Bross M, Rockwell D (2014) Flow structure on a simultaneously pitching and rotating wing. J Fluid Mech 756:354–383. doi: 10.1017/jfm.2014.458 CrossRefGoogle Scholar
  2. Bross M, Ozen CA, Rockwell D (2013) Flow structure on a rotating wing: effect of steady incident flow. Phys Fluids. doi: 10.1063/1.4816632 Google Scholar
  3. Carr ZR, Chen C, Ringuette MJ (2013a) Finite-span rotating wings: three-dimensional vortex formation and variations with aspect ratio. Exp Fluids 54:1444–1470. doi: 10.1007/s00348-012-1444-8 CrossRefGoogle Scholar
  4. Carr ZR, DeVoria AC, Ringuette MJ (2013b) Aspect ratio effects on the leading-edge circulation and forces of rotating flat-plate wings. In: AIAA Paper 2013-0675Google Scholar
  5. Carr ZR, DeVoria AC, Ringuette MJ (2015) Aspect-ratio effects on rotating wings: circulation and forces. J Fluid Mech 767:497–525. doi: 10.1017/jfm.2015.44 CrossRefGoogle Scholar
  6. Dickson WB, Dickinson MH (2004) The effect of advance ratio on the aerodynamics of revolving wings. J Exp Biol 207:4269–4281. doi: 10.1242/jeb.01266 CrossRefGoogle Scholar
  7. Ekaterinaris JA, Platzer M (1998) Computation predictions of airfoil dynamic stall. Prog Aerosp Sci 33:759–846. doi: 10.1016/S0376-0421(97)00012-2 CrossRefGoogle Scholar
  8. Eldredge JD, Wang C (2010) High-fidelity simulations and low-ordering modeling of a rapidly pitching plate. In: AIAA Paper 2010-4281Google Scholar
  9. Ellington CP, van den Berg C, Willmott AP, Thomas ALR (1996) Leading-edge vortices in insect flight. Nature 384:626–630CrossRefGoogle Scholar
  10. Garmann DJ, Visbal MR (2011) Numerical investigation of transitional flow over a rapidly pitching plate. Phys Fluids. doi: 10.1063/1.3626407 Google Scholar
  11. Garmann DJ, Visbal MR (2013) A numerical study of hovering wings undergoing revolving or translating motions. In: AIAA Paper 2013-3052Google Scholar
  12. Garmann DJ, Visbal MR (2014) Dynamics of revolving wings for various aspect ratios. J Fluid Mech 748:932–956. doi: 10.1017/jfm.2014.212 CrossRefGoogle Scholar
  13. Garmann DJ, Visbal MR, Orkwis PD (2013) Three-dimensional flow structure and aerodynamic loading on a revolving wing. Phys Fluids. doi: 10.1063/1.4794753 Google Scholar
  14. Harbig RR, Sheridan J, Thompson MC (2014) The role of advance ratio and aspect ratio in determining leading-edge vortex stability for flapping flight. J Fluid Mech 751:71–105. doi: 10.1017/jfm.2014.262 CrossRefMathSciNetGoogle Scholar
  15. Hartloper C, Kinzel M, Rival DE (2013) On the competition between leading-edge and tip-vortex growth for a pitching plate. Exp Fluids 54:1447–1458. doi: 10.1007/s00348-012-1447-5 CrossRefGoogle Scholar
  16. Hunt JCR, Wray AA, Moin P (1988) Eddies, streams, and convergence zones in turbulent flows. In: Studying turbulence using numerical simulation databases, vol 2, pp 193–208Google Scholar
  17. Jones AR, Babinsky H (2011) Reynolds number effects on leading edge vortex development on a waving wing. Exp Fluids 10:197–210. doi: 10.1007/s00348-010-1037-3 CrossRefGoogle Scholar
  18. Kim D, Gharib M (2010) Experimental study of three-dimensional vortex structures in translating and rotating plates. Exp Fluids 49:329–339. doi: 10.1007/s00348-010-0872-6 CrossRefGoogle Scholar
  19. Lehmann FO, Dickinson MH (1998) The control of wing kinematics and flight forces in fruit flies. J Exp Biol 401:385–401Google Scholar
  20. Lentink D, Dickinson MH (2009a) Biofluiddynamic scaling of flapping, spinning and translating fins and wings. J Exp Biol 212:2691–2704. doi: 10.1242/jeb.022251 CrossRefGoogle Scholar
  21. Lentink D, Dickinson MH (2009b) Rotational accelerations stabilize leading edge vortices on revolving fly wings. J Exp Biol 212:2705–2719. doi: 10.1242/jeb.022269 CrossRefGoogle Scholar
  22. Manar F, Medina A, Jones AR (2014) Tip vortex structure and aerodynamic loading on rotating wings in confined spaces. Exp Fluids 55:1815–1833. doi: 10.1007/s00348-014-1815-4 CrossRefGoogle Scholar
  23. McCroskey WJ (1982) Unsteady airfoils. Annu Rev Fluid Mech 14:285–311. doi: 10.1146/annurev.fl.14.010182.001441 CrossRefGoogle Scholar
  24. Moffatt HK (1969) The degree of knottedness of tangled vortex lines. J Fluid Mech 35:117–129CrossRefzbMATHGoogle Scholar
  25. Ozen CA, Rockwell D (2011) Flow structure on a rotating plate. Exp Fluids 52:207–223. doi: 10.1007/s00348-011-1215-y CrossRefGoogle Scholar
  26. Ozen CA, Rockwell D (2012) Three-dimensional vortex structure on a rotating wing. J Fluid Mech 707:1–10. doi: 10.1017/jfm.2012.298 CrossRefGoogle Scholar
  27. Percin M, Van Oudheusden BW (2015) Three-dimensional flow structures and unsteady forces on pitching and surging revolving flat plates. Exp Fluids 56:1–19. doi: 10.1007/s00348-015-1915-9 CrossRefGoogle Scholar
  28. Percin M, Ziegler L, Van Oudheusden BW (2014) Flow around a suddenly accelerated rotating plate at low reynolds number. In: 17th International symposium on applications of laser techniques to fluid mechanicsGoogle Scholar
  29. Poelma C, Dickson WB, Dickinson MH (2006) Time-resolved reconstruction of the full velocity field around a dynamically-scaled flapping wing. Exp Fluids 41:213–225. doi: 10.1007/s00348-006-0172-3 CrossRefGoogle Scholar
  30. Sane SP (2003) The aerodynamics of insect flight. J Exp Biol 206:4191–4208. doi: 10.1242/jeb.00663 CrossRefGoogle Scholar
  31. Shih C, Lourenco L, Dommelen LVan, Krothapallij A (1992) Unsteady flow past an airfoil pitching at a constant rate. AIAA J 30:1153–1161. doi: 10.2514/3.11045 CrossRefGoogle Scholar
  32. Shyy W, Aono H, Chimakurthi SK, Trizila P, Kang C-KCK, Cesnik CES, Liu H (2010) Recent progress in flapping wing aerodynamics and aeroelasticity. Prog Aerosp Sci 46:284–327. doi: 10.1016/j.paerosci.2010.01.001 CrossRefGoogle Scholar
  33. Visbal MR (2012) Flow structure and unsteady loading over a pitching and perching low-aspect-ratio wing. In: AIAA Paper 2012-3279Google Scholar
  34. Visbal MR, Shang JS (1989) Investigation of the flow structure around a rapidly pitching airfoil. AIAA J 27:1044–1051CrossRefGoogle Scholar
  35. Wojcik CJ, Buchholz JHJ (2014) Vorticity transport in the leading-edge vortex on a rotating blade. J Fluid Mech 743:249–261. doi: 10.1017/jfm.2014.18 CrossRefGoogle Scholar
  36. Wolfinger M, Rockwell D (2014) Flow structure on a rotating wing: effect of radius of gyration. J Fluid Mech 755:83–110. doi: 10.1017/jfm.2014.383 CrossRefGoogle Scholar
  37. Yilmaz TO, Rockwell D (2012) Flow structure on finite-span wings due to pitch-up motion. J Fluid Mech 691:518–545. doi: 10.1017/jfm.2012.490 CrossRefzbMATHGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  1. 1.Department of Mechanical Engineering and MechanicsLehigh UniversityBethlehemUSA

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