馬蹄渦
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馬蹄渦（英語：horseshoe vortex）是一種簡化的機翼渦系模型，由跟隨機翼運動的等環量附着渦（bound vortex）和在左、右翼尖處形成的翼尖渦組成。這三條渦線形成類似馬蹄的形狀，馬蹄渦也因之得名。[1][2]此外，當機翼在流場中從靜止開始起動時，另有一起動渦從機翼後脫落，但很快因黏性而耗散。[3]同時，遠離飛行器的翼尖渦也同樣因此而耗散。
馬蹄渦模型假設環量沿翼展不變（此時由庫塔-儒可夫斯基定理可知升力亦沿翼展不變），但這與實際情形並不相符。在更接近實際的升力線理論中，旋渦強度沿翼展方向不斷變化，強度的改變導致渦從整個機翼後緣脫落形成渦面，而非僅在左、右翼尖處形成渦線。[5]
參考文獻[編輯]
- ^ Millikan, Clark B., Aerodynamics of the Airplane, Figure 1.35
- ^ McCormick, Barnes W., Aerodynamics, Aeronautics, and Flight Mechanics, Chapter 3
- ^ Shed Vortex. NASA Glenn Research Center. [April 11, 2015]. （原始內容存檔於2015-04-06）.
- ^ McCormick, Barnes W., Aerodynamics, Aeronautics, and Flight Mechanics, Chapter 4
- ^ McCormick, Barnes W., Aerodynamics, Aeronautics, and Flight Mechanics, Figure 4.21
- Anderson, John D. (2007), Fundamentals of Aerodynamics, Section 5.3 (4th ed.), McGraw-Hill, New York NY. ISBN 978-0-07-295046-5
- Clancy, L.J. (1975), Aerodynamics, Section 8.10, Pitman Publishing Limited, London ISBN 0-273-01120-0
- Cook, N.J. (1985), The designer's guide to wind loading of building structures, Part 1, Butterworths, London ISBN 0-408-00870-9
- McCormick, Barnes W., (1979), Aerodynamics, Aeronautics, and Flight Mechanics, John Wiley & Sons, Inc. New York ISBN 0-471-03032-5
- Millikan, Clark B., (1941), Aerodynamics of the Airplane, Section 1-6 John Wiley and Sons, Inc., New York
- Penwarden, A.D., Wise, A.F.E., (1975) Wind environment around buildings, HMSO, London ISBN 0-11-670533-7.
- Piercy, N.A.V. (1944), Elementary Aerodynamics, Article 213, The English Universities Press Ltd., London.
- Von Mises, Richard, (1959), Theory of Flight, Chapter IX - section 4, Dover Publications, Inc., New York ISBN 0-486-60541-8