Experimental Investigation of Local Flexible Surface on Aerodynamic Effects for Finite Wing with NACA0018 Section

The experimental study is conducted in low-speed wind tunnel in order to explore the effects of flexible surface on the aerodynamic performance of NACA0018 finite wing. In this purpose, lift and drag force of the wing measured using six axes load cell over the angle of attack 0°-18° at different Reynolds numbers. Moreover, surface oil flow visualization experiments are performed to depict the flow structure over wing. The flexible wing remarkably improves aerodynamic performance at Re=3×104, and it also enhances the lift coefficient and diminishes the drag coefficient. The stall angle is delayed from 2.5° to 7°. It is observed that stall angle is shifted further angle of attack when Reynolds number increased. However, the effect of flexible surface on the aerodynamic performance diminishes with increasing Reynolds number. Furthermore, the observed tip vortex and laminar separation bubble significantly influence the surface flow structure.