An Aerodynamic Analysis of Bird Wings as Fixed Aerofoils
An Aerodynamic Analysis of Bird Wings as Fixed Aerofoils
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发表时间：
1981-02
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通讯作者：
P. Withers
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作者：
P. Withers
在雷诺数为1-5 × 104的范围内，研究了鸟翼的气动特性，并与展弦比、弯度、头部半径和最大厚度位置等形态参数进行了关联。鸟类、昆虫和飞机机翼的空气动力特性之间的许多质的差异主要归因于它们不同的雷诺数。鸟翼在比翼型低的雷诺数下工作，具有高的最小阻力系数（0.03 - 0.13）、低的最大升力系数（0.8 - 1.2）和低的最大升阻比（3-17）。鸟类和昆虫翅膀的翼型效率系数（0.2 - 0.8）比传统翼型（0.9 - 0.95）低，这是因为它们的雷诺数低，翼型阻力大，而不是因为动物翅膀的机械效率降低。对于鸟的翅膀，显然有一个升力和阻力性能之间的权衡。低阻力的鸟翼通常具有低的最大升力系数，而具有高的最大升力系数的机翼具有高的阻力系数。如压力分布数据所示，流过鸟翼的气流模式与低雷诺数下飞机机翼的空气动力学理论以及所观察到的升力和阻力系数是一致的。
The aerodynamic properties of bird wings were examined at Reynolds numbers of 1-5 × 10 4 and were correlated with morphological parameters such as apsect ratio, camber, nose radius and position of maximum thickness. The many qualitative differences between the aerodynamic properties of bird, insect and aeroplane wings are attributable mainly to their differing Reynolds numbers. Bird wings, which operate at lower Reynolds numbers than aerofoils, have high minimum drag coefficients (0·03-0·13), low maximum lift coefficients (0·8-1·2) and low maximum lift/drag ratios (3–17). Bird and insect wings have low aerofoil efficiency factors (0·2-0·8) compared to conventional aerofoils (0·9-0·95) because of their low Reynolds numbers and high profile drag, rather than because of a reduced mechanical efficiency of animal wings. For bird wings there is clearly a trade-off between lift and drag performance. Bird wings with low drag generally had low maximum lift coefficients whereas wings with high maximum lift coefficients had high drag coefficients. The pattern of air flow over bird wings, as indicated by pressure-distribution data, is consistent with aerodynamic theory for aeroplane wings at low Reynolds numbers, and with the observed lift and drag coefficients.