Aerodynamics of wing-assisted incline running in birds
Aerodynamics of wing-assisted incline running in birds
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DOI：
10.1242/jeb.001701
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发表时间：
2007-05-15
影响因子：
2.8
通讯作者：
Dial, Kenneth P.
中科院分区：
文献类型：
--
作者：
Tobalske, Bret W.;Dial, Kenneth P.
翼助斜坡跑（Wing-assisted incline running，WAIR）是一种鸟类拍打翅膀以帮助后肢爬上斜坡的运动形式。WAIR用于地面鸟类的逃逸，早熟鸟类的这种行为的个体发生被认为是代表一种类似于动力鸟类飞行进化过程中过渡适应状态的模型。为了开始揭示襟翼运行的空气动力学，我们使用了数字粒子图像测速仪（DPIV），并测量了空气速度，涡度，环流和增加的质量在后的chukar paradise Aleclovenchukar，因为他们从事WAIR（倾斜65- 85度; N= 7鸟）和上升飞行（85度，N=2）。为了估计升力和冲量，我们将DPIV数据与同伴研究中的三维机翼运动学数据相结合。使用三个年龄组评估升力产生的个体发育：不能飞行的幼鸟[孵化后6-8天（d.p.h.）]和能飞的幼鱼（25-28天）和成虫（45天以上）。所有三个年龄段的鸟类，包括部分出现的，对称的翅膀羽毛的幼鸟，产生循环与他们的翅膀，并表现出一个唤醒结构，包括离散的涡环脱落一次每下冲程。在WAIR期间，涡环的脉冲相对于水平方向定向为45 +/- 5度，相对于基底定向为21 +/- 4度。涡核环流和诱导速度的绝对值随年龄的增加而增加。WAIR中所有年龄段的正常循环相似，但成年人在飞行过程中比襟翼跑高67%。在WAIR期间，婴儿的估计升力为体重的6.6%，青少年和成人的估计升力为体重的63%至86%。在飞行过程中，平均升力为体重的110%。我们的研究结果首次揭示，从机翼的升力，而不是机翼惯性或轮廓阻力，是主要负责加速身体向基板在WAIR，部分开发的翅膀，还没有能够飞行，可以产生有用的升力在WAIR。我们预测，神经肌肉控制或功率输出，而不是外部翅膀形态，限制了鸟类在发展过程中的飞行能力的发作。
Wing-assisted incline running (WAIR) is a form of locomotion in which a bird flaps its wings to aid its hindlimbs in climbing a slope. WAIR is used for escape in ground birds, and the ontogeny of this behavior in precocial birds has been suggested to represent a model analogous to transitional adaptive states during the evolution of powered avian flight. To begin to reveal the aerodynamics of flap-running, we used digital particle image velocimetry ( DPIV) and measured air velocity, vorticity, circulation and added mass in the wake of chukar partridge Alectoris chukar as they engaged in WAIR ( incline 65- 85 degrees; N= 7 birds) and ascending flight (85 degrees, N=2). To estimate lift and impulse, we coupled our DPIV data with three-dimensional wing kinematics from a companion study. The ontogeny of lift production was evaluated using three age classes: baby birds incapable of flight [6-8 days post hatching (d.p.h.)] and volant juveniles (25-28 days) and adults (45+ days). All three age classes of birds, including baby birds with partially emerged, symmetrical wing feathers, generated circulation with their wings and exhibited a wake structure that consisted of discrete vortex rings shed once per downstroke. Impulse of the vortex rings during WAIR was directed 45 +/- 5 degrees relative to horizontal and 21 +/- 4 degrees relative to the substrate. Absolute values of circulation in vortex cores and induced velocity increased with increasing age. Normalized circulation was similar among all ages in WAIR but 67% greater in adults during flight compared with flaprunning. Estimated lift during WAIR was 6.6% of body weight in babies and between 63 and 86% of body weight in juveniles and adults. During flight, average lift was 110% of body weight. Our results reveal for the first time that lift from the wings, rather than wing inertia or profile drag, is primarily responsible for accelerating the body toward the substrate during WAIR, and that partially developed wings, not yet capable of flight, can produce useful lift during WAIR. We predict that neuromuscular control or power output, rather than external wing morphology, constrain the onset of flight ability during development in birds.