Peng Liansong, Zheng Mengzong, Pan Tianyu, Su Guanting, Li Qiushi
School of Energy and Power Engineering, Beihang University, Beijing 100191, People's Republic of China.
Research Institute of Aero-Engine, Beihang University, Beijing 100083, People's Republic of China.
R Soc Open Sci. 2021 Aug 25;8(8):202275. doi: 10.1098/rsos.202275. eCollection 2021 Aug.
Dragonflies possess two pairs of wings and the interactions between forewing (FW) and hindwing (HW) play an important role in dragonfly flight. The effects of tandem-wing (TW) interactions on the aerodynamic performance of dragonfly hovering have been investigated. Numerical simulations of single-wing hovering without interactions and TW hovering with interactions are conducted and compared. It is found that the TW interactions reduce the lift coefficient of FW and HW by 7.36% and 20.25% and also decrease the aerodynamic power and efficiency. The above effects are mainly caused by the interaction between the vortex structures of the FW and the HW, which makes the pressure of the wing surface and the flow field near the wings change. During the observations of dragonfly flight, it is found that the phase difference () is not fixed. To explore the influence of phase difference on aerodynamic performance, TW hovering with different phase differences is studied. The results show that at = 22.5°, dragonflies produce the maximum lift which is more than 20% of the body weight with high efficiency; at = 180°, dragonflies generate the same lift as the body weight.
蜻蜓拥有两对翅膀，前翅（FW）和后翅（HW）之间的相互作用在蜻蜓飞行中起着重要作用。已经研究了串联翼（TW）相互作用对蜻蜓悬停空气动力学性能的影响。进行并比较了无相互作用的单翼悬停和有相互作用的TW悬停的数值模拟。发现TW相互作用使FW和HW的升力系数分别降低了7.36%和20.25%，同时也降低了空气动力功率和效率。上述影响主要是由FW和HW涡旋结构之间的相互作用引起的，这使得机翼表面的压力和机翼附近的流场发生变化。在观察蜻蜓飞行时，发现相位差（）并不固定。为了探究相位差对空气动力学性能的影响，研究了不同相位差的TW悬停。结果表明，在 = 22.5°时，蜻蜓产生的最大升力超过体重的20%，且效率很高；在 = 180°时，蜻蜓产生的升力与体重相同。
