Aerodynamics of bird flight

Abstract

Abstract. Unlike airplanes birds must have either flapping or oscillating wings (the hummingbird). Only such wings can produce both lift and thrust -two sine qua non attributes of flying.The bird wings have several possibilities how to obtain the same functions as airplane wings. All are realized by the system of flight feathers. Birds have also the capabilities of adjusting the shape of the wing according to what the immediate flight situation demands, as well as of responding almost immediately to conditions the flow environment dictates, such as wind gusts, object avoidance, target tracking, etc. In bird aerodynamics also the tail plays an important role. To fly, wings impart downward momentum to the surrounding air and obtain lift by reaction. How this is achieved under various flight situations (cruise flight, hovering, landing, etc.), and what the role is of the wing-generated vortices in producing lift and thrust is discussed.The issue of studying bird flight experimentally from in vivo or in vitro experiments is also briefly discussed.

Correlation between wing bone microstructure and different flight styles: The case of the griffon vulture (gyps fulvus) and greater flamingo (phoenicopterus roseus)

“…This assertion agrees with the fact that the primary remiges that insert into the hand skeleton are often positioned upwards during the soaring flight as the distal part of the wing is weakly involved in contrasting the torsion stress. The suppleness of some primary remiges on the wingtips of large soaring birds, such as griffon vultures, allows the reduction of air vortices, providing more stability to the wingtips (Baufrère, 2009; Dvořàk, 2016). This last movement of the last remiges on the wingtips, which characterize vultures worldwide, is particularly evident during the landing maneuver, when a great precision of movements is required (Dhawan, 1991).…”

Calculation of the Air Displaced by a Wing

“…buoyancy where a fluid (air or water) needs to be constantly displaced downwards to allow an object to maintain buoyancy. For example, planes achieve 'dynamic' (active) buoyancy as the wings are constantly pushing air down [4][5][6][7][8][9].…”

“…It is noted that birds are known to use vortices to boost lift. [9] 5. This analysis works well when the wing has a 1-meter Wing Reach, when displacing the air.…”

Designing and producing a bird-inspired unmanned sailplane

“…The thermals formed as a result of temperature differences are of great importance as they enable raptors and migratory birds to fly across great distances. Since the thermals are vertical air columns, birds should circle in these air columns (Aldheeb et al , 2016; Dvořák, 2016 Wing loading directly affects the radius of turn, causing geographic isolation in soaring birds. Large raptors (Vultures, eagles, hawks), storks and other migratory birds, which have been adapted to soaring flight with high wing area wings, circle in the thermals very efficiently (Videler, 2006).…”