翼间干涉效应对蜻蜓悬停气动性能的影响

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.