Experimental Mechanics

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

Aerodynamic Performance of a Gliding Swallowtail Butterfly Wing Model

  • H. Park
  • K. Bae
  • B. Lee
  • W.-P. Jeon
  • H. ChoiEmail author


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.


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



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).


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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

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