Effects of aeroelasticity on flapping wing propulsion

Interest in flapping wing propulsion has increased significantly in the past decade due to the potential applications in the design and development of micro air vehicles. In comparison to the wing kinematics, there has been relatively less attention given to the aeroelasticity of flapping wings. Recently, there have been some studies on the effects of flexibility of flapping wings through parameters like Reynolds numbers, wing structure and material properties. These studies have modelled the wings with varying levels of fidelity, from flat plates to detailed models of wing structure. The purpose of this paper is to provide a critical review of the progress of research on the effects of aeroelasticity on flapping wing flight. The contributions made so far will be highlighted, the gaps identified and potential areas for further study and challenges discussed. Preliminary results on the numerical analysis of a real insect, a bumblebee (Bombus terrestris), typically flying at Re≈10 ³, will also be presented. As a first step, the insect wings and body are assumed as rigid bodies. The computational results agree well with the experimental measurements, with a vortex-ring pattern observed during downstroke. Comparison between wing and wing-body models indicates that the unique vortex pattern might not result from having a wide thorax.