AERODYNAMICS OF TWO-DIMENSIONAL FLAPPING WING(S)

Abstract

This thesis experimentally investigated the aerodynamics of a two-dimensional wing in hover flight and tandem wings under forward flight. Numerical simulation, as an auxiliary tool, was also employed. Firstly, the effect of phase angle of a hovering wing was examined. The results revealed that maximum lift and lift-to-drag ratio were achieved in the advanced pitching, due to the mechanism of rotational effect and favorable wing-wake interaction. Delayed pitching is detrimental to the lift generation. Secondly, the influences of phase difference and wing distance between tandem wings subjected to symmetric or asymmetric flapping kinematics were studied. It was found that the combination of phase difference and wing distance determines how the rear wing interacts with the wake of the front wing. The interaction significantly affects the aerodynamic performance of the rear wing through altering the direction of the incoming velocity of the rear wing, thereby changing its effective angle of attack.