OJFD  Vol.4 No.4 , December 2014
Aerodynamics of the Cupped Wings during Peregrine Falcon’s Diving Flight
ABSTRACT
During a dive peregrine falcons can reach velocities of more than 320 km/h and makes themselves the fastest animals in the world. The aerodynamic mechanisms involved are not fully understood yet and the search for a conclusive answer to this fact motivates the three-dimensional (3-D) flow study. Especially the cupped wing configuration which is a unique feature of the wing shape in falcon peregrine dive is our focus herein. In particular, the flow in the gap between the main body and the cupped wing is studied to understand how this flow interacts with the body and to what extend it affects the integral forces of lift and drag. Characteristic shapes of the wings while diving are studied with regard to their aerodynamics using computational fluid dynamics (CFD). The results of the numerical simulations via ICEM CFD and OpenFOAM show predominant flow structures around the body surface and in the wake of the falcon model such as a pair of body vortices and tip vortices. The drag for the cupped wing profile is reduced in relation to the configuration of opened wings (without cupped-like profile) while lift is increased. The purpose of this study is primarily the basic research of the aerodynamic mechanisms during the falcon’s diving flight. The results could be important for maintaining good maneuverability at high speeds in the aviation sector.

Cite this paper
Ponitz, B. , Triep, M. and Brücker, C. (2014) Aerodynamics of the Cupped Wings during Peregrine Falcon’s Diving Flight. Open Journal of Fluid Dynamics, 4, 363-372. doi: 10.4236/ojfd.2014.44027.
References
[1]   del Hoyo, J., Elliott, A., Sargatal, J. and Collar, N.J. (1999) Handbook of the Birds of the World. Vol. 5, Lynx Edicions, Barcelona.

[2]   Podbregar, N. (2013) Das Geheimnis des Fliegens—Tierischen Flugkünstlern auf der Spur: Strategien der Evolution. Springer, Berlin and Heidelberg, 227-243.

[3]   Tucker, V.A. and Parrott, G.C. (1970) Aerodynamics of Gliding Flight in a Falcon and Other Birds. Journal of Experimental Biology, 52, 345-367.

[4]   Orton, D.A. (1975) The Speed of a Peregrine’s Dive. The Field, 588-590.

[5]   Brown, L.A. (1976) British Birds of Prey. Collins, London.

[6]   Alerstam, T. (1987) Radar Observations of the Stoop of the Peregrine Falcon Falco Peregrinus and the Goshawk Accipiter Gentilis. Ibis, 129, 267-273.
http://dx.doi.org/10.1111/j.1474-919X.1987.tb03207.x

[7]   Savage, C. (1992) Peregrine Falcons. Sierra Club, San Francisco.

[8]   Clark, W.S. (1995) How Fast Is the Fastest Bird? WildBird, 9, 42-43.

[9]   Tucker, V.A. (1998) Gliding Flight: Speed and Acceleration of Ideal Falcons during Diving and Pull Out. Journal of Experimental Biology, 201, 403-414.

[10]   Franklin, D.C. (1999) Evidence of Disarray amongst Granivorous Bird Assemblages in the Savannas of Northern Australia, a Region of Sparse Human Settlement. Biological Conservation, 90, 53-68.
http://dx.doi.org/10.1016/S0006-3207(99)00010-5

[11]   Nachtigall, W. (1975) Vogelflügel und Gleitflug Einführung in die aerodynamische Betrachtungsweise des Flügels. Journal für Ornithologie, 116, 1-38.
http://dx.doi.org/10.1007/BF01643073

[12]   Nachtigall, W. (1998) Der Gleitflug von Vögeln. Physik in unserer Zeit, 1, 25-29.

[13]   Lentink, D., Müller, U.K., Stamhuis, E.J., de Kat, R., van Gestel, W., Veldhuis, L.L.M., et al. (2007) How Swifts Control Their Glide Performance with Morphing Wings. Nature, 446, 1082-1085.
http://dx.doi.org/10.1038/nature05733

[14]   Ratcliffe, D.A. (1980) The Peregrine Falcon. Buteo Books, Vermillion.

[15]   Hustler, K. (1983) Breeding Biology of the Peregrine Falcon in Zimbabwe. Ostrich, 54, 161-171.
http://dx.doi.org/10.1080/00306525.1983.9634466

[16]   Tucker, V.A. (1990) Body Drag, Feathers Drag and Interference Drag of the Mounting Strut in a Peregrine Falcon, Falco peregrinus. Journal of Experimental Biology, 149, 449-468.

[17]   Seitz, K. (1999) Vertical Flight. NAFA Journal, 38, 68-72.

[18]   Ponitz, B., Schmitz, A., Fischer, D., Bleckmann, H. and Brücker, C. (2014) Diving-Flight Aerodynamics of a Peregrine Falcon (Falco peregrinus). PLoS ONE, 9, e86506.
http://dx.doi.org/10.1371/journal.pone.0086506

[19]   Jeong, J. and Hussain, F. (1995) On the Identification of a Vortex. Journal of Fluid Mechanics, 285, 69-94.
http://dx.doi.org/10.1017/S0022112095000462

[20]   Krasny, R. (1987) Computation of Vortex Sheet Roll-Up in the Trefftz Plane. Journal of Fluid Mechanics, 184, 123- 155.
http://dx.doi.org/10.1017/S0022112087002830

[21]   Cabral, B. and Leedom, L.C. (1993) Imaging Vector Fields Using Line Integral Convolution. In: Proceedings of ACM SIGGRAPH’93, Anaheim, 2-6 August 1993, 263-270.

[22]   Schmitz, A., Ponitz, B., Brücker, C., Schmitz, H., Herweg, J. and Bleckmann, H. (2014) Morphological Properties of the Last Primaries, the Tail Feathers, and the Alulae of Accipiter nisus, Columba livia, Falco peregrinus, and Falco tinnunculus. Journal of Morphology, Early View.
http://dx.doi.org/10.1002/jmor.20317

 
 
Top