The effect of twist morphing on aerodynamic performance of finite wing at low Reynolds number

This study experimentally investigates the effect of twist morphing on the aerodynamic characteristics of a finite wing at low Reynolds numbers (Re). As the base model, a NACA 0018 airfoil with an aspect ratio of 4 is used. The twist morphing configuration is obtained by applying camber deflection at the wing tip, while maintaining a symmetrical root section. Two morphing cases with trailing-edge deflection angles of θ = 2.5° and 5° are examined at Re = 7×104 and 10×104. Force measurements and surface oil visualization experiments are carried out to depict the flow structure. The results show that twisted wings generate positive lift at an angle of attack of α=0°. The lift coefficient (CL) of the twisted morphing wings increases by up to 40% compared to the baseline case. Flow visualizations reveal that laminar separation bubbles (LSBs) occur at low angles of attack, and its size decreases with the increasing angle of attack. The interaction between tip vortices and LSBs further influences the local flow behaviour. The obtained results demonstrate that twist morphing can enhance aerodynamic efficiency and contribute to roll control in uncrewed aerial vehicles operating under low Reynolds number conditions.