Flapping Wing Aerodynamics

Birds, bats, and insects flap their wings to produce lift as well as thrust. The aerodynamics associated with flapping wings can be enhanced by large-scale vortical flow structures by wing kinematics, wing shapes, and flexible wing structures. Consequently, with appropriate kinematics, frequency, and amplitude, flapping wings can generate substantially higher lift and perform well beyond stall angle of attack for fixed wings. In this chapter, we highlight the fluid physics associated with low Reynolds number flapping wings, including leading edge vortices, pitch-up rotation, wake capture, clap-and-fling mechanisms, and tip vortices, as well as the impact of wing flexibility on flapping wing aerodynamics.