Enhancing aerodynamic performance using biomimetic wavy trailing edges on aircraft wing at low Reynolds number

This study investigates the aerodynamic effects of biomimetic wavy trailing edges inspired by natural designs, focusing on their application to a swept-back NACA 0012 airfoil under free-flight conditions. Numerical simulations were conducted using a three-dimensional numerical model with k-ω SST turbulence modeling at a Reynolds number of 3 × 10⁴. The study was performed under steady-state conditions. Reynolds-Averaged Navier-Stokes (RANS) were used in the simulation. The baseline wing was modified with sinusoidal trailing edges, varying wave amplitude and wavelength in both chordwise and spanwise directions to assess their impact on lift, drag, and stall characteristics. Experimental validation was conducted in a low subsonic speed wind tunnel using 3D-printed scaled models, with comprehensive data collection on lift and drag coefficients, pressure distribution, and flow visualization. The results indicate that the wavy trailing-edge configuration maintains comparable lift to the clean wing at low angles of attack (AOA < 8°), while providing substantial aerodynamic enhancement beyond 8°, with improved lift generation and delayed stall. This demonstrates its potential for improving post-stall stability and aerodynamic efficiency in low-Reynolds-number flight regimes. Results demonstrate that a moderate wave amplitude of 20% tip chord length at 8° angle of attack enhances lift by 11.8%. The optimum parametric wavy wing delays the stall by approximate 6° associated with an increase in C_Lmax by 31% compared to a conventional straight edge. The findings highlight the potential of wavy trailing edges for improving aerodynamic efficiency and stability, particularly for small aircraft and UAVs.