Short-amplitude high-frequency wing strokes determine the aerodynamics of honeybee flight
Short-amplitude high-frequency wing strokes determine the aerodynamics of honeybee flight
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DOI：
10.1073/pnas.0506590102
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发表时间：
2005-12-13
影响因子：
11.1
通讯作者：
Dickinson, MH
中科院分区：
文献类型：
--
作者：
Altshuler, DL;Dickson, WB;Dickinson, MH
大多数昆虫被认为是通过产生一个前沿涡流来飞行的，当它通过一次冲程转换时，这个涡流仍然附着在机翼上。到目前为止，在所研究的物种中，冲程幅度很大，大部分气动力是在冲程中途产生的，此时平移速度最高。在这里，我们演示了蜜蜂使用另一种策略，以相对较低的敲击幅度(大约90度)和较高的翼拍频率(大约230赫兹)盘旋。当在动态缩放的机器人上测量时，蜜蜂翅膀的运动学在每个划程的开始、中期和结束时产生显著的力峰，表明在冲程反转时额外的不稳定机构的重要性。当被要求在低密度氦氧中飞行时，蜜蜂的反应是保持几乎恒定的翼拍频率，同时将拍击幅度增加近50%。我们通过使用人工运动学模式来研究这种机翼运动变化的空气动力学后果，在人工运动学模式中，振幅以5度的增量系统地增加。为了区分冲程速度的气动影响和由振幅引起的影响，我们在恒频和恒速条件下进行了这一分析。结果表明，划水反转时的非定常力对悬停时的净上升力有很大的贡献，但随着划水幅度和飞行功率的增加，其作用逐渐减弱。我们认为，蜜蜂独特的运动学可能反映了增加负荷能力的专门化，也可能反映了其飞行肌肉的生理限制。
Most insects are thought to fly by creating a leading-edge vortex that remains attached to the wing as it translates through a stroke. In the species examined so far, stroke amplitude is large, and most of the aerodynamic force is produced halfway through a stroke when translation velocities are highest. Here we demonstrate that honeybees use an alternative strategy, hovering with relatively low stroke amplitude (approximate to 90 degrees) and high wingbeat frequency (approximate to 230 Hz). When measured on a dynamically scaled robot, the kinematics of honeybee wings generate prominent force peaks during the beginning, middle, and end of each stroke, indicating the importance of additional unsteady mechanisms at stroke reversal. When challenged to fly in low-density heliox, bees responded by maintaining nearly constant wingbeat frequency while increasing stroke amplitude by nearly 50%. We examined the aerodynamic consequences of this change in wing motion by using artificial kinematic patterns in which amplitude was systematically increased in 5 degrees increments. To separate the aerodynamic effects of stroke velocity from those due to amplitude, we performed this analysis under both constant frequency and constant velocity conditions. The results indicate that unsteady forces during stroke reversal make a large contribution to net upward force during hovering but play a diminished role as the animal increases stroke amplitude and flight power. We suggest that the peculiar kinematics of bees may reflect either a specialization for increasing load capacity or a physiological limitation of their flight muscles.