Soaring and Gliding Flight of the Black Vulture

1958 ◽  
Vol 35 (2) ◽  
pp. 280-285
Author(s):  
B. G. NEWMAN
Keyword(s):  
Flow Separation ◽  
Angle Of Attack ◽  
High Angle ◽  
High Angle Of Attack ◽  
Wing Area ◽  
Wing Span ◽  
Gliding Flight ◽  
Black Vulture ◽  
Wing Geometry

1. The soaring and gliding performance of the black vulture has been analysed and the following conclusions are drawn. 2. The wing span of the bird is altered in flight so that it may perform two tasks efficiently. First, that it may soar in rising currents of air for which a low sinking speed and thus a large wing span are required. Secondly, that it may penetrate into wind without undue loss of height for which a reduced wing area is desirable. Adjustment of the wing geometry towards the optimum soaring configuration is achieved by bending forward and opening the primary tip feathers. 3. Since the airflow readily separates from the flat primary feathers at high angle of attack, these feathers, which are emarginated, are parted to form slots. The alula also presumably assists in delaying the flow separation over the primaries. 4. It is unlikely that the opening of the primaries reduces the vortex drag.

Aerodynamics of Gliding Flight of a Black Vulture Coragyps Atratus

1970 ◽  
Vol 53 (2) ◽  
pp. 363-374 ◽  
Author(s):  
G. CHRISTIAN PARROTT
Keyword(s):  
Wind Tunnel ◽  
Wing Area ◽  
Drag Coefficients ◽  
Wing Span ◽  
Drag Forces ◽  
Gliding Flight ◽  
Black Vulture ◽  
Air Speed

1. A black vulture (mass = 1.79 kg) gliding freely in a wind tunnel adjusted its wing span and wing area as its air speed and glide angle changed from 9.9 to 16.8 m/s and from 4.8° to 7.9°, respectively. 2. The minimum sinking speed was 1.09 m/s at an air speed of 11.3 m/s. 3. The maximum ratio of lift to drag forces was 11.6 at an air speed of 13.9 m/s. 4. Parasite drag coefficients for the vulture are similar to those for conventional airfoils and do not support the contention that black vultures have unusually low values of parasite drag.

Passive control of flow separation over delta wings at high angle-of-attack

1996 ◽  
Author(s):  
R. Van Dyken ◽  
K. Yu ◽  
E. Gutmark ◽  
I. Tuncer ◽  
M. Platzer ◽  
...  
Keyword(s):  
Flow Separation ◽  
Passive Control ◽  
Angle Of Attack ◽  
High Angle ◽  
High Angle Of Attack ◽  
Delta Wings ◽  
Control Of Flow

scholarly journals Leading Edge Blowing to Mimic and Enhance the Serration Effects for Aerofoil

2021 ◽  
Vol 11 (6) ◽  
pp. 2593
Author(s):  
Yasir Al-Okbi ◽  
Tze Pei Chong ◽  
Oksana Stalnov
Keyword(s):  
Boundary Layer ◽  
Angle Of Attack ◽  
Leading Edge ◽  
Boundary Layer Separation ◽  
Shear Instability ◽  
Vortical Flow ◽  
High Angle ◽  
High Angle Of Attack ◽  
Layer Separation ◽  
Aerodynamic Performances

Leading edge serration is now a well-established and effective passive control device for the reduction of turbulence–leading edge interaction noise, and for the suppression of boundary layer separation at high angle of attack. It is envisaged that leading edge blowing could produce the same mechanisms as those produced by a serrated leading edge to enhance the aeroacoustics and aerodynamic performances of aerofoil. Aeroacoustically, injection of mass airflow from the leading edge (against the incoming turbulent flow) can be an effective mechanism to decrease the turbulence intensity, and/or alter the stagnation point. According to classical theory on the aerofoil leading edge noise, there is a potential for the leading edge blowing to reduce the level of turbulence–leading edge interaction noise radiation. Aerodynamically, after the mixing between the injected air and the incoming flow, a shear instability is likely to be triggered owing to the different flow directions. The resulting vortical flow will then propagate along the main flow direction across the aerofoil surface. These vortical flows generated indirectly owing to the leading edge blowing could also be effective to mitigate boundary layer separation at high angle of attack. The objectives of this paper are to validate these hypotheses, and combine the serration and blowing together on the leading edge to harvest further improvement on the aeroacoustics and aerodynamic performances. Results presented in this paper strongly indicate that leading edge blowing, which is an active flow control method, can indeed mimic and even enhance the bio-inspired leading edge serration effectively.

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