Aerodynamic behavior of tandem corrugated airfoils in gliding flight of dragonflies

Dragonflies are remarkable flyers with two pairs of thin, corrugated wings that allow for agile maneuvering and efficient gliding. Although much attention has been paid to their flapping flight, dragonflies also exploit gliding during long-distance migration, such as from the Indian subcontinent to Africa. The geometry of the corrugated wings offers both structural and aerodynamic advantages, enabling thin, lightweight construction and potentially enhancing performance at low Reynolds numbers. We investigate the aerodynamic behavior of corrugated airfoils in gliding conditions, focusing on flow regimes relevant to both dragonflies and micro-aerial unmanned vehicles (MAVs). Direct Numerical Simulations are conducted on single and tandem wing configurations to assess performance. To reduce computational cost, we employed a Reynolds-averaged Navier-Stokes-assisted DNS methodology for flow over corrugated airfoils at low Reynolds numbers. The results show that tandem configurations can achieve aerodynamic efficiencies of around 10, comparable to single wing cases. In addition, the optimal position for the tandem wing configuration is identified, enhancing overall aerodynamic performance. Furthermore, the corrugated profile demonstrates resilience to free-stream turbulence, suggesting robustness in unsteady environments. The findings highlight the aerodynamic viability and potential design benefits of corrugated wings inspired by Dragonflies for MAV applications.