Aerodynamic Modeling of a Flapping Membrane Wing Using Motion Tracking Experiments

Abstract

An analytical model of flapping membrane wing aerodynamics using experimental kinematic data is presented. An alternative to computational fluid dynamics, this experimental method tracks small reflective markers placed on two ornithopter membrane wings. Time varying three dimensional data of the wing kinematics and the corresponding aerodynamic loads were recorded for various flapping frequencies. The wing shape data was used to form an analytical aerodynamic model that uses blade element theory and quasi-steady aerodynamics to account for the local twist, stroke angle, membrane shape, wing velocity and acceleration. Results from the aerodynamic model show adequate correlation between the magnitude of lift and thrust produced but some phase errors exist between the measured and calculated force curves. This analytical model can be improved by comparison with a RANS CFD solver which provides insight into the fluid behavior. Implications on the membrane wing design are also presented.