蜻蜓在悬停飞行过程中，通过控制翅膀的运动规律，进行前后翅相位差为180°的扑翼运动。为了分析两对翅膀之间的干涉效应对悬停气动性能的影响，利用计算流体力学手段对蜻蜓悬停状态的串列扑翼和单对翅扑翼进行模拟。通过对两种模式下的流场进行分析，并计算对比了悬停效率、气动力及气动功率的数据，发现了悬停状态下翼间干涉的气动效应：尾迹集中效应和来流偏折效应。尾迹集中效应可以减少翅膀附近的涡耗散和尾迹耗散，提高悬停效率；来流偏折效应可以通过减小后翅在下拍过程中的来流攻角，从而降低前缘涡的尺寸和强度，降低悬停功率。数值结果表明：在运动规律相同的情况下，与单独拍动的前翅和后翅进行的悬停相比，串列双翅悬停的效率分别提高了18.6%和25.5%，功率分别降低了4.8%和14.0%。
Dragonflies employ tandem-wing hovering with a phase difference of 180°. To investigate the influence of tandem-wing interactions on the aerodynamics of dragonfly hovering, we simulated two cases of tandem-wing hovering and single-wing hovering through CFD. Analyses of the flow fields and comparison of the hover efficiency, aerodynamic force and aerodynamic power of the two cases obtained the aerodynamic effects of the tandem-wing interactions: the ‘wake-gathering’ effect and ‘inflow-bending’ effect. The ‘wake-gathering’ effect can reduce vortex dissipation and wake dissipation near the wings to improve the hovering efficiency, and the ‘inflow-bending’ effect can weaken the size and strength of the leading edge vortex by reducing the angle of attack of the hindwing during the downstroke to reduce power. The numerical results show that, compared with single-forewing and single-hindwing hovering with the same kinematics, the efficiency of tandem-wing hovering is increased by 18.6% and 25.5%, respectively, and the power is reduced by 4.8% and 14.0%, respectively.
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