Aerodynamic aspects of formation flight in birds

Hummel, Dietrich

doi:10.1016/0022-5193(83)90110-8

Cited by 159 publications

(115 citation statements)

References 11 publications

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“…The energy savings of formation locomotion are predominately supported by theoretical work (i.e. Breder 1965, 1976Belyayev & Zuyev 1969, Lissaman & Schollenberger 1970, Weihs 1973, Higdon & Corrsin 1978, Badgerow & Hainsworth 1981, Hummel 1983, Kshatriya & Blake 1992 while empirical quantifications are rare. Only few studies have measured oxygen consumption rate (Parker 1973, Abrahams & Colgan 1985, Fish 1994, Herskin & Steffensen 1998, heart rate (Weimerskirch ABSTRACT: Cetacean mother-calf dyads demonstrate formation locomotion that may provide hydrodynamic and/or social benefits.…”

Section: Introductionmentioning

confidence: 97%

“…Breder 1965, Lissaman & Schollenberger 1970 advantages. Although applied to all modes of locomotion including walking (Fancy & White 1985), saving energy by moving in formation is considered most practical in flying (Lissaman & Schollenberger 1970, Hummel 1983) and swimming (Breder 1965, Weihs 1973. Energetic advantages are possible because animals set the fluid around them moving (air or water) and these fluid movements in some circumstances can be taken advantage of by another individual to decrease its energy cost of locomotion (for review see Alexander 2004).…”

Section: Introductionmentioning

confidence: 99%

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Infant position in mother-calf dolphin pairs: formation locomotion with hydrodynamic benefits

Noren

Edwards²

2011

Mar. Ecol. Prog. Ser.

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Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Infant position in mother-calf dolphin pairs: formation locomotion with hydrodynamic benefits

Noren

Edwards²

2011

Mar. Ecol. Prog. Ser.

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“…It has been observed that birds tend to align on a line connecting their eyes to their wing tips. 5) There is also an assumption 18) that a strong male takes the lead in a V formation if birds in the formation are blood relatives, and that, if they are not related, a U formation in which all birds take equal loads results due to the unwillingness of the birds to take the lead. In the present research, these biological factors were not taken into account.…”

Section: Mode (B)mentioning

confidence: 99%

“…3,4) The optimal formation pattern has also been studied. Lissaman et al 1) and Hummel 5,6) found that the power required by each bird in a formation becomes uniform if they fly in a U formation. Filippone 7) derived a similar result.…”

Section: Background and Purpose Of Studymentioning

confidence: 99%

A Study on Optimal Pattern and Leader Shift of Formation Flight

Kawabe

2007

Trans. Japan Soc. Aero. S Sci.

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The aerodynamics of formation flight are studied by modeling wings using a horseshoe vortex. During flight in formation, wings receive upwash created by other wings, and the required power consequently decreases. The leading wing in a V formation receives less benefit, while in a U formation, the power reduction rate remains identical over all wings. In long-distance flights, the U formation is optimal. However, when the process of shifting the leader position in a V formation is considered, as is often observed in actual bird flocks in long-distance flights, the power reduction rates of all wings converge into the same value after several shifts. This value is identical to that of the U formation.Key Words: Flight Dynamics, Formation Flight, Horseshoe Vortex, Flight Power Reduction, Leader Shift Background and Purpose of StudyBirds often fly in formation. Since the lifting-line theory was proposed by Prandtl, a variety of research has been done on formation flight based on this theory. In the 1970s, Lissaman et al. 1) reported that birds attain higher aerodynamic efficiency by flying in a V formation, extending their flight distance. Recently, Weimerskirch et al. 2) found from measurements of white pelicans during formation flight that wing flapping rate and heart beat rate are less than normally observed during solo flight. The Autonomous Formation Flight Project by NASA, Boeing and UCLA proved that an airplane in the rear position in a formation consumes less fuel during a cruise flight. Flight control of two airplanes in formation has also been attracting attention. 3,4)The optimal formation pattern has also been studied. Lissaman et al. 1) and Hummel 5,6) found that the power required by each bird in a formation becomes uniform if they fly in a U formation. Filippone 7) derived a similar result. In actual airplane operations, however, the importance of visually confirming the position of other airplanes in the formation is more important than maximizing the aerodynamic efficiency, and the two-airplane formation is usually used. The formation pattern and leadership are scarcely altered. Although the V formation is used for securing maximum visibility when more than two airplanes fly together, they never fly as close to each other as seen in the formation flights of birds.Birds also often fly in a V formation in long-distance flights in spite of its unfavorable power requirement compared to a U formation. It is also often observed that the leader position in a V formation is taken alternately by different birds. This suggests that the leader shift in a V formation has some aerodynamic advantage other than securing visibility. Analysis of formation flights taking leader shifts into consideration, which will contribute to the understanding of the formation flight of birds, has not been carried out so far. In this paper, first the optimal formation pattern is analyzed by approximating the wing with a horseshoe vortex and determining the reduction ratio of the required power obtained by flying in formation. Vario...

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“…Flight in flock formation is expected to alleviate flight cost by reducing the induced drag of individual birds [17,18], which should reduce the characteristic flight speeds U mr and U mt , respectively [19]. However, the few observations available where flight speed was measured in relation to flock size suggest that airspeed increases with increasing flock size [20].…”

Section: Introductionmentioning

confidence: 99%

Ecology of tern flight in relation to wind, topography and aerodynamic theory

Hedenström

Åkesson

2016

Phil. Trans. R. Soc. B

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One contribution of 17 to a theme issue 'Moving in a moving medium: new perspectives on flight'. Flight is an economical mode of locomotion, because it is both fast and relatively cheap per unit of distance, enabling birds to migrate long distances and obtain food over large areas. The power required to fly follows a U-shaped function in relation to airspeed, from which context dependent 'optimal' flight speeds can be derived. Crosswinds will displace birds away from their intended track unless they make compensatory adjustments of heading and airspeed. We report on flight track measurements in five geometrically similar tern species ranging one magnitude in body mass, from both migration and the breeding season at the island of Ö land in the Baltic Sea. When leaving the southern point of Ö land, migrating Arctic and common terns made a 608 shift in track direction, probably guided by a distant landmark. Terns adjusted both airspeed and heading in relation to tail and side wind, where coastlines facilitated compensation. Airspeed also depended on ecological context (searching versus not searching for food), and it increased with flock size. Species-specific maximum range speed agreed with predicted speeds from a new aerodynamic theory. Our study shows that the selection of airspeed is a behavioural trait that depended on a complex blend of internal and external factors.This article is part of the themed issue 'Moving in a moving medium: new perspectives on flight'.

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Aerodynamic aspects of formation flight in birds

Cited by 159 publications

References 11 publications

Infant position in mother-calf dolphin pairs: formation locomotion with hydrodynamic benefits

Infant position in mother-calf dolphin pairs: formation locomotion with hydrodynamic benefits

A Study on Optimal Pattern and Leader Shift of Formation Flight

Ecology of tern flight in relation to wind, topography and aerodynamic theory

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