COMPUTATIONAL INVESTIGATION AND FLOW FIELD ANALYSIS OF FLEXIBLE WING FOR HUMMINGBIRD-LIKE HOVERING MOTION

Abstract

Flapping wing micro aerial vehicles are studied as the substitute for fixed and rotary wing micro aerial vehicles because of the advantages such as agility, maneuverability and employability in confined environments. Hummingbird’s sustainable hovering capability inspires many researchers to develop MAVs with similar dynamics. But in previous studies, either kinematics or wing shape of the hummingbird is changed. In this study, a wing of a ruby-throated hummingbird is modeled as an insect wing using a membrane with curved leading-edge stiffeners and straight surface stiffeners. The same shape and kinematics are used for the design. The effect of flexibility on the aerodynamic performance of a wing at hovering flight has been studied numerically by using a Fluid-Structure Interaction scheme at a characteristics Reynolds Number of 3000. The computational model is validated by experimental results selected from the literature. Different wings have been developed by using the different position and thickness of the surface stiffener. The chord and span-wise flexural stiffness of designed wings match well of the insects of the same size. A rigid wing is designed, and its analysis is performed to compare the aerodynamic performance with the flexible wing. In the case of different stiffener positions, the best performing wing has an average lift coefficient of 0.51. In addition, in the case stiffener thickness, the best performing wing has an average lift coefficient of 0.56. In comparison with the average lift coefficient of 0.48 for the rigid wing and 0.61 for the ruby-throated hummingbird wing, the highest lift coefficient of 0.56 was obtained by the flexible wing modelled in this work. The results show that flexibility has positive effect on the lift production of hummingbird-like wing in hover. It was also been found that flexible wing can support the weight of a modelled bird of 3.4 grams.