Study On Aerodynamic Performance Of Dragonfly Flapping Airfoil By Using Tree Structure Adaptive Mesh Method

As the important bionic object of flutter micro air vehicle design, dragonfly flapping flight isefficient and agile. In recent years, with a lot of experimental and numerical investigating about thedragonfly flapping flight, it has been made greater progress. However, because of the complicatedflow mechanism, many flow details of flapping wing have not been known. In this thesis, a newnumerical algorithm was used to calculate the flow field around dragonfly flapping airfoil. Thecomputational domain is spatially discrete by using a Quadtree/octree structure adaptive mesh.Compared with other existing algorithms, this algorithm can more effectively capture the flappingwing’s wake and get more real and comprehensive flow details due to the dynamic adaptive meshtechnology.In this thesis, the effects of three kinematics parameters, Reynolds numbers, flapping amplitudeand phase difference on the aerodynamic performance have been investigated. The results show thatthe aerodynamic performance of flapping airfoil is sensitive to Reynolds number when the Reynoldsnumber is low, but it becomes less sensitive with the increase of Reynolds number. When theReynolds number keeps a certain value but flapping amplitude and phase difference change, theaerodynamic performance of flapping airfoil promotes linearly as flapping amplitude growth.However, the original flapping mode change will slightly change when the phase difference change.So for flapping flight at low Reynolds number, the phase difference and flapping amplitude are thekey factors to affect the dynamic performance of flapping wing.