Effect of Gurney Flap On the Aerodynamic Performance of a Flapping Foil: MAV Application

Abstract

Even with its small size, the Gurney flap can help considerably in increasing the lift of foils and wings. To exploit this feature, the objective of this research was to numerically study the effects of this flow control device on the aerodynamic performance of oscillating foils for MAV applications. Three sets of each important parameter were selected: the height (0.01c, 0.04c, 0.16c), angle (45°, 90°, 135°) and location from trailing edge (T.E, 0.05c, 0.1c). A two-dimensional laminar, incompressible Navier-Stokes equation solver was used to computationally investigate the effect of the Gurney flap on the aerodynamic performance of a flat plate (chord length = 10 mm and thickness = 0.03c). It was found that the best aerodynamic performance was obtained when the Gurney flap was installed at the trailing edge with a height of 0.04c and mount angle of 90°. The height of the Gurney ?ap had a major impact on aerodynamic performance. Results showed an increase of 23.5% in mean lift coefficient, 15.5% in maximum lift coefficient, and 5% in power economy as compared to ?at plate which is accredited to the increase in effective camber and the formation of counter-rotating vortices, decreasing the adverse pressure gradient. The weakening of counter-rotating vortices downstream of Gurney ?ap could also be the contributing factor to its good performance. The results suggest that the Gurney ?ap may be useful in enhancing the performance of wings for bioinspired flapping wing MAVs.