Unsteady Aerodynamics in Ornithopter Flight

The investigation of unsteady aerodynamics is becoming a more attractive topic of research in enhancing flight capabilities. Natural flyers such as birds and insects can undergo flight maneuvers that are very difficult or impossible to accomplish with man-made flyers and current classical aerodynamic theory. Modeling the unsteady phenomena produced by flapping wings is important to the understanding of these maneuvers, with possible applications to aircraft flight. We investigate numerically simulating the unsteady aerodynamics generated by flapping wings using the two seperate approaches of rotational lift and dynamic stall. A low order quasi-steady model based on rotational lift and a revised version based on dynamic stall are presented. Both concepts are analyzed using simulated results, with experimental data produced with matching kinematics as a basis of comparison. The numerically generated force curves are used to explore the characteristics and distinguishing features of both approaches, as well as how well they capture the salient features of the experimentally produced forces.