空飛ぶハミングバードの空気力学

Douglas R Warrick¹, Bret W Tobalske, Donald R Powers

¹Department of Zoology, Oregon State University, 3029 Cordley Hall, Corvallis, Oregon 97331, USA. warrickd@science.oregonstate.edu

Nature

|June 24, 2005

まとめ

コリバーは,昆虫とは異なり,ダウンストローク中にほとんどの浮揚力を発生します. 翼の逆転によって引き起こされるこの力非対称性は,渦のダイナミクスの類似性にもかかわらず,鳥の飛行を区別します.

科学分野:

バイオメカニクスバイオメカニクス
エアロダイナミクスエアロダイナミクス
鳥類学鳥類学とは,鳥類学である.

背景:

コリバー (Trochilidae) は,飛ぶために昆虫のような空気力学メカニズムを使用するとしばしば考えられています.
コリブリの翼の振動における運動対称性は,上下運動の間,同じ力持ちを生成することを示唆している.
この仮定は,空気力学モデルとハミングバード飛行の経験的研究に影響を与えます.

研究の目的:

鳥のハミングバードで浮いている時の力産生非対称性を調査する.
蜂鳥の空気力学メカニズムと昆虫の空気力学メカニズムを比較する.
羽の動力学と形状学がハミングバード飛行における役割を分析する.

主な方法:

デジタル粒子画像速度測定法 (DPIV) を用いて,上空を飛ぶルフスハミングバード (Selasphorus rufus) の足跡を測定した.
分析は,エアロダイナミック・フォースを推論するために,ウェイク構造に焦点を当てた.
翼の運動学と形態学は,力発生に関連して検討された.

主要な成果:

コリバーは,重力の不対称性を有しており,ダウンストロークでは重量の75%を,アップストロークでは重量の25%を支えている.
アップストローク中の翼の逆転が,この力非対称性に寄与している可能性が高い.
ダウンストローク中に観測された最先端の渦は,昆虫と同様に,低いレイノルズ数で動作することを示唆しています.

結論:

羽ばたきするハミングバードには,力不対称性が特徴であり,上下運動の同等の貢献と対照的である.
渦の動態は昆虫と似ているが,ハミングバードの飛行は鳥の体型によって異なる.
この研究は,ハミングバードが採用しているユニークな空気力学戦略を強調しています.

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