Gust response of an airfoil with a flexible trailing edge

Given that the variable-camber continuous trailing-edge flap can enhance the environmental adaptability of wings, this study experimentally investigates the gust response of an airfoil with a flexible trailing edge. The flexible trailing edge comprises 30% of the airfoil chord length and can adaptively undergo chordwise deformation under flow pressure. The unsteady lift, surrounding flow field, and deformation of the flexible trailing edge are synchronously measured. Compared with the rigid airfoil, the time-averaged lift coefficient of the flexible airfoil increases under gust incoming condition, whereas the standard deviation of the lift coefficient decreases. In the case of a low angle of attack, two representative flow structures with distinct frequencies may be obtained, corresponding to the shear layer and shedding vortex. The shear layer above the upper surface of airfoil fluctuates at gust frequencies. The high-frequency vortex shedding in the wake region is significantly affected by the shear layer. The oscillation of the flexible trailing edge is fully coupled with nearby flow fluctuations, which is divided into four stages in one gust cycle. Additionally, compared with the rigid airfoil, the amplitudes of the shear-layer and velocity fluctuations for the flexible airfoil decrease, indicating that the flexible trailing edge can reduce the influence of gusts on the flow field. At a high angle of attack, dynamic stall occurs. A leading-edge vortex develops above the flexible trailing edge. The induced negative pressure causes the flexible trailing edge to deflect significantly upward, thereby weakening the strength of the leading-edge vortex and alleviating the gust load.