Ministry-of-Education Key Laboratory of Fluid Mechanics, Institute of Fluid Mechanics, Beihang University, Beijing 100191, China.
Phys Rev E. 2020 Jan;101(1-1):012412. doi: 10.1103/PhysRevE.101.012412.
To investigate the way in which very small insects compensate for unilateral wing damage, we measured the wing kinematics of a very small insect, a phorid fly (Megaselia scalaris), with 16.7% wing area loss in the outer part of the left wing and a normal counterpart, and we computed the aerodynamic forces and power expenditures of the phorid flies. Our major findings are the following. The phorid fly compensates for unilateral wing damage by increasing the stroke amplitude and the deviation angle of the damaged wing (the large deviation angle gives the wing a deep U-shaped wing path), unlike the medium and large insects studied previously, which compensate for the unilateral wing damage mainly by increasing the stroke amplitude of the damaged wing. The increased stroke amplitude and the deep U-shaped wing path give the damaged wing a larger wing velocity during its flapping motion and a rapid downward acceleration in the beginning of the upstroke, which enable the damaged wing to generate the required vertical force for weight support. However, the larger wing velocity of the damaged wing also generates larger horizontal and side forces, increasing the resultant aerodynamic force of the damaged wing. Due to the larger aerodynamic force and the smaller wing area, the wing loading of the damaged wing is 25% larger than that of the wings of the normal phorid fly; this may greatly shorten the life of the damaged wing. Furthermore, because the damaged wing has much larger angular velocity and produces larger aerodynamic moment compared with the intact wing of the damaged phorid fly, the aerodynamic power consumed by the damaged wing is 38% larger than that by the intact wing, i.e., the energy distribution between the damaged and intact wings is highly asymmetrical; this may greatly increase the muscle wastage of the damaged side.
为了研究非常小的昆虫如何补偿单侧翅膀损伤，我们测量了一只非常小的昆虫——腐食虻（Megaselia scalaris）的翅膀运动学，这只昆虫的左翅外部分损失了 16.7%的翼面积，同时还有一个正常的对照，我们计算了腐食虻的空气动力和功耗。我们的主要发现如下。与之前研究的中型和大型昆虫不同，腐食虻通过增加受损翅膀的冲程幅度和偏转角（大的偏转角使翅膀形成深的 U 形翅膀路径）来补偿单侧翅膀损伤，而不是主要通过增加受损翅膀的冲程幅度来补偿。增加的冲程幅度和深的 U 形翅膀路径使受损翅膀在拍打运动中具有更大的翅膀速度和在上升行程开始时的快速向下加速度，这使受损翅膀能够产生支撑重量所需的垂直力。然而，受损翅膀更大的翅膀速度也会产生更大的水平和侧向力，增加受损翅膀的总空气动力。由于更大的空气动力和更小的翼面积，受损翅膀的翼载比正常腐食虻的翅膀大 25%；这可能会大大缩短受损翅膀的寿命。此外，由于受损翅膀的角速度大得多，产生的空气动力矩也比受损腐食虻的完整翅膀大，因此受损翅膀消耗的空气动力功率比完整翅膀大 38%，即受损和完整翅膀之间的能量分布极不对称；这可能会大大增加受损侧的肌肉消耗。
