NUMERICAL SIMULATION OF PITCHING MOTION EFFECTS ON THE AERODYNAMIC PERFORMANCE OF DRAGONFLY-LIKE FLAPPING WING

Dragonflies have remarkable flight skills and their excellent flight performance has attracted persistent attention. The multi-degree-of-freedom flapping kinematics and interaction of the tandem wings might account for their extraordinary flight skills. In this paper, the effects of pitching motion on the aerodynamic performance of a dragonfly-like flapping wing have been numerically studied. A transient numerical method based on the overset mesh technique is used to simulate the flapping and pitching movements. Different pitching amplitudes have been evaluated as the forewing and hindwing flap in counter-stroking during the hovering process. It is found that the pitching motion has an obvious influence on the tandem wings' aerodynamic performance, and there is a reasonable pitching amplitude to make the hovering vertical force optimal. Additionally, the interaction of the tandem configuration will lead to an obvious fluctuation in the aerodynamic force. The research in this paper is helpful to understand the flight mechanism of dragonflies flight.