Research on the influence of flapping mode on aerodynamic performance of flapping wings based on CFD simulation

DOI:	10.11809/bqzbgcxb2023.01.009
Keywords:	flapping mode; CFD; three dimensional flapping wing; vortex structure; aerodynamic performance
Abstract:	To analyze the effect of motion mode of wings on aerodynamic performance, this paper establishes an aerodynamic performance model of multi degree of freedom flapping wings based on CFD software. Firstly, a 3D bionic flapping wing model is established considering the bionic shape of the wing. The multi DOF aerodynamic function of the flapping wings is defined by a user defined function (UDF). On this basis, the lift and thrust coefficients of the wings under different DOF flapping modes are investigated by CFD. Finally, the effects of flapping modes on aerodynamic force of 3D flapping wings are revealed by pressure contour and vortex structure of the wing surface. The results show that, when the flapping wing flies horizontally forward against the wind, the torsional motion accelerates the shedding process of the trailing edge vortex, enhances the strength of the trailing edge vortex, and increases the lift force by 0.25 times and the thrust coefficient by 4.69 times. The strength and shape of the trailing edge vortex are further increased by horizontal swing motion, which significantly improves the thrust performance of the flapping wings, and, when the horizontal movement frequency regulation parameter k=2, the lift and thrust performance of the flapping wings will be further improved.
Published:	2023-01-28
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