Experimental Mechanics

, Volume 50, Issue 9, pp 1313–1321 | Cite as

Aerodynamic Performance of a Gliding Swallowtail Butterfly Wing Model

Article

Abstract

In the present study, we perform a wind-tunnel experiment to investigate the aerodynamic performance of a gliding swallowtail-butterfly wing model having a low aspect ratio. The drag, lift and pitching moment are directly measured using a 6-axis force/torque sensor. The lift coefficient increases rapidly at attack angles less than 10° and then slowly at larger attack angles. The lift coefficient does not fall off rapidly even at quite high angles of attack, showing the characteristics of low-aspect-ratio wings. On the other hand, the drag coefficient increases more rapidly at higher angles of attack due to the increase in the effective area responsible for the drag. The maximum lift-to-drag ratio of the present modeled swallowtail butterfly wing is larger than those of wings of fruitfly and bumblebee, and even comparable to those of wings of birds such as the petrel and starling. From the measurement of pitching moment, we show that the modeled swallowtail butterfly wing has a longitudinal static stability. Flow visualization shows that the flow separated from the leading edge reattaches on the wing surface at α < 15°, forming a small separation bubble, and full separation occurs at α ≥ 15°. On the other hand, strong wing-tip vortices are observed in the wake at α ≥ 5° and they are an important source of the lift as well as the main reason for broad stall. Finally, in the absence of long hind-wing tails, the lift and longitudinal static stability are reduced, indicating that the hind-wing tails play an important role in enhancing the aerodynamic performance.

Keywords

Gliding Hind-wing tails Lift-to-drag ratio Longitudinal static stability Low-aspect-ratio wing Modeled swallowtail butterfly wing 

Notes

Acknowledgments

This work was supported by the National Research Laboratory Program of Ministry of Education, Science and Technology, Korea (R0A-2006-000-10180-0). This work was also partly supported by the Korea Research Foundation Grant (MOEHRD; KRF-J03001) and the WCU Program (R31-2008-000-10083-0).

References

  1. 1.
    Shyy W, Lian Y, Tang J, Viieru D, Liu H (2008) Aerodynamics of low reynolds number flyers. Cambridge University Press, New YorkCrossRefGoogle Scholar
  2. 2.
    Brodsky AK (1994) The evolution of insect flight. Oxford University Press, New YorkGoogle Scholar
  3. 3.
    Dudley R (2000) The biomechanics of insect flight. Form, function, evolution. Princeton University Press, PrincetonGoogle Scholar
  4. 4.
    Gibo DL, Pallett MJ (1979) Soaring flight of monarch butterflies, Danaus Plexippus (Lepidoptera: Danaidae), during the late summer migration in southern Ontario. Can J Zool 57:1393–1401CrossRefGoogle Scholar
  5. 5.
    Preston-Mafham R, Preston-Mafham K (2004) Butterflies of the world. Facts on File, New YorkGoogle Scholar
  6. 6.
    Brodsky AK (1991) Vortex formation in the tethered flight of the peacock butterfly Inachis Io L. (Lepidoptera, Nymphalidae) and some aspects of insect flight evolution. J Exp Biol 161:77–95Google Scholar
  7. 7.
    Ellington CP, van den Berg C, Willmott AP, Thomas ALR (1996) Leading-edge vortices in insect flight. Nature 384:626–630CrossRefGoogle Scholar
  8. 8.
    Srygley RB, Thomas ALR (2002) Unconventional lift-generating mechanisms in free-flying butterflies. Nature 420:660–664CrossRefGoogle Scholar
  9. 9.
    Nachtigall W (1976) Wing movements and the generation of aerodynamic forces by some medium-sized insects. In: Rainey RC (ed) Insect flight. Blackwell Scientific Publications, Oxford, pp 31–47Google Scholar
  10. 10.
    Buckholz RH (1986) The functional role of wing corrugations in living systems. J Fluids Eng 108:93–97CrossRefGoogle Scholar
  11. 11.
    Wootton RJ (1993) Leading edge section and asymmetric twisting in the wings of flying butterflies (Insecta, Papilionoidea). J Exp Biol 180:105–117Google Scholar
  12. 12.
    Berwaerts K, van Dyck H, Aerts P (2002) Does flight morphology relate to flight performance? An experimental test with the butterfly Pararge aegeria. Funct Ecol 16:484–491CrossRefGoogle Scholar
  13. 13.
    Betts CR, Wootton RJ (1988) Wing shape and flight behaviour in butterflies (Lepidoptera: Papilionoidea and Hesperioidea): a preliminary analysis. J Exp Biol 138:271–288Google Scholar
  14. 14.
    Martin LJ, Carpenter PW (1977) Flow-visualization experiments on butterflies in simulated gliding flight. In: Nachtigall W (ed) The physiology of movement: biomechanics. Fischer, Stuttgart, pp 307–315Google Scholar
  15. 15.
    Nachtigall W (1974) Insects in flight. McGraw-Hill, New YorkGoogle Scholar
  16. 16.
    Cech R, Tudor G (2005) Butterflies of the East Coast: an observer’s guide. Princeton University Press, PrincetonGoogle Scholar
  17. 17.
    Barlow JB, Rae WH Jr, Pope A (1999) Low-speed wind tunnel testing. Wiley, New YorkGoogle Scholar
  18. 18.
    Mueller TJ, Torres GE (2001) Aerodynamic characteristics of low aspect ratio wings at low Reynolds numbers. In: Fixed and flapping wing aerodynamics for micro air vehicle applications. American Institute of Aeronautics and Astronautics, Inc., Virginia, pp 115–141Google Scholar
  19. 19.
    Thomas ALR, Taylor GK (2001) Animal flight dynamics I. Stability in gliding flight. J Theor Biol 212:399–424CrossRefGoogle Scholar
  20. 20.
    Wakeling JM, Ellington CP (1997) Dragonfly flight I. Gliding flight and steady-state aerodynamic forces. J Exp Biol 200:543–556Google Scholar
  21. 21.
    Vogel S (1967) Flight in drosophila III. Aerodynamic characteristics of fly wings and wing models. J Exp Biol 46:431–443Google Scholar
  22. 22.
    Jensen M (1956) Biology and physics of locust flight III. The aerodynamics of locust flight. Philos Trans R Soc Lond B 239:511–552CrossRefGoogle Scholar
  23. 23.
    Withers PC (1981) An aerodynamic analysis of bird wings as fixed aerofoils. J Exp Biol 90:143–162Google Scholar
  24. 24.
    Dudley R, Ellington CP (1990) Mechanics of forward flight in bumblebees II. Quasi-steady lift and power requirements. J Exp Biol 148:53–88Google Scholar
  25. 25.
    Nachtigall W (1977) Die Aerodynamische Polare des Tipula-Flugels undeine Einrichtung zur halbautomatischen Polarenaufnahme. In: Nachtigall W (ed) The physiology of movement: biomechanics. Fischer, Stuttgart, pp 347–352Google Scholar
  26. 26.
    Willmott AP, Ellington CP (1997) The mechanics of flight in the hawkmoth Manduca sexta. 2. Aerodynamic consequences of kinematic and morphological variation. J Exp Biol 200:2723–2745Google Scholar
  27. 27.
    Vogel S (1994) Life in moving fluids. Princeton University Press, PrincetonGoogle Scholar
  28. 28.
    Lian Y, Shyy W (2003) Three-dimensional fluid-structure interactions of a membrane wing for micro air vehicle applications. AIAA Paper 2003-1726Google Scholar
  29. 29.
    Mueller TJ, DeLaurier JD (2003) Aerodynamics of small vehicles. Annu Rev Fluid Mech 35:89–111CrossRefGoogle Scholar
  30. 30.
    Hoerner SF (1985) Fluid-dynamic lift. Hoerner, BakersfieldGoogle Scholar
  31. 31.
    Williamson CHK (1985) Evolution of a single wake behind a pair of bluff bodies. J Fluid Mech 159:1–18CrossRefGoogle Scholar
  32. 32.
    Kang S (2003) Characteristics of flow over two circular cylinders in a side-by-side arrangement at low Reynolds numbers. Phys Fluids 15:2486–2498CrossRefGoogle Scholar
  33. 33.
    Kolar V, Lyn DA, Rodi W (1997) Ensemble-averaged measurements in the turbulent near wake of two side-by-side square cylinders. J Fluid Mech 346:201–237CrossRefGoogle Scholar
  34. 34.
    Sumner D, Wong SST, Price SJ, Paidoussis MP (1999) Fluid behavior of side-by-side circular cylinder in steady cross-flow. J Fluids Struct 13:309–338CrossRefGoogle Scholar
  35. 35.
    Zdravkovich MM (2003) Flow around circular cylinders vol. 2: applications. Oxford University Press, New YorkGoogle Scholar
  36. 36.
    Zhou Y, Zhang HJ, Yiu MW (2002) The turbulence wake of two side-by-side circular cylinders. J Fluid Mech 458:303–332MATHCrossRefGoogle Scholar

Copyright information

© Society for Experimental Mechanics 2010

Authors and Affiliations

  1. 1.School of Mechanical and Aerospace EngineeringSeoul National UniversitySeoulKorea
  2. 2.Center for Turbulence and Flow Control Research, Institute of Advanced Machinery and DesignSeoul National UniversitySeoulKorea

Personalised recommendations