The influence of airfoil kinematics on the formation of leading-edge vortices in bio-inspired flight
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The formation process of leading-edge vortices has been investigated experimentally using Particle Image Velocimetry. Various airfoil kinematics have been tested, including asymmetric and peak-shifted plunging motions, and are evaluated for Re = 30,000 and a reduced frequency range of 0.2 ≤ k ≤ 0.33. By measuring the growth in the leading-edge vortex during the dynamic-stall process, the vortex pinch-off process is examined based on the concept of an optimal vortex formation time. The various kinematics are then evaluated with respect to their associated vortex strength, timing and convection into the wake.
KeywordsVortex Particle Image Velocimetry Vortex Pair Sinusoidal Motion Effective Angle
The authors would like to thank Dr. Michael Ol from Wright-Patterson AFB for the fruitful discussions regarding Theodorsen’s theory. This research was supported by the Deutsche Forschungsgemeinschaft (DFG) within the national priority program entitled Nature-Inspired Fluid Mechanics (SPP1207).
- Ellington CP (1999) The novel aerodynamics of insect flight: applications to micro-air vehicles. J Exp Biol 202:3439–3448Google Scholar
- Kuessner HG (1936) Zusammenfassender bericht ueber den instationaeren auftrieb von fluegeln. Luftfahrtforschung 13:410–424Google Scholar
- Lian Y, Ol MV, Shyy W (2008) Comparative study of pitch-plunge airfoil aerodynamics at transitional reynolds number. 46th AIAA aerospace sciences meeting and exhibit, AIAA-2008-652-812, Reno, USAGoogle Scholar
- Nerger D, Kaehler CJ, Radespiel R (2003) Zeitaufgeloeste piv-messungen an einem schwingenden sd7003-profil bei re=60000. 11 GALA Fachtagung, Braunschweig, GermanyGoogle Scholar
- Ol MV, McAuliffe BR, Hanff ES, Scholz U, Kaehler C (2005) Comparison of laminar separation bubble measurements on a low reynolds number airfoil in three facilities. 35th AIAA fluid dynamics conference and exhibit, AIAA-2005-5149, Toronto, CanadaGoogle Scholar
- Rival D, Tropea C (2009) Characteristics of pitching and plunging airfoils under dynamic-stall conditions. 47th AIAA aerospace sciences meeting and exhibit, AIAA-2009-0537, Orlando, USAGoogle Scholar
- Selig M, Guglielmo J, Broeren A, Giguere P (1995) Summary of low-speed airfoil data. SoarTech Publications, Virginia Beach, USAGoogle Scholar
- Theodorsen T (1935) General theory of aerodynamic instability and the mechanisms of flutter. NACA Report No 496Google Scholar