Sound generation by three-dimensional flapping wings during hovering flight

Abstract

Flapping flight strategy is widely adopted by insects and birds, which has drawn considerable attentions due to its excellent aerodynamic performance. It is worth noting that the good performance and great agility is also achieved with low noise. To apply this flight strategy to engineering, it is necessary to conduct corresponding studies to understand both the aerodynamics and the associated acoustics of the flapping wing. In this paper, the sound generated by flexible flapping wings during hovering flight is numerically studied by using an immersed boundary method. A series of parameters including the wing shape, wing-to-fluid mass ratio and wing flexibility are systematically examined at a low Reynolds number. It is found that appropriate flexibilities of the wing enhance the aerodynamic performance and reduce the noise generation.