Effect of Chordwise Flexibility on Flapping Wing Aerodynamics

In this study, the effect of chordwise flexibility has been investigated experimentally for a plunging foil. A Digital Particle Image Velocimetry (DPIV) system is used to determine instantaneous velocity and vorticity fields around and in the near-wake of the wings in conjunction with simultaneous direct force/moment measurements. The aerodynamic/hydrodynamic performance is studied for rigid and flexible wings undergoing plunge motion at different amplitudes and frequencies in a freestream of Re = 10 000. The thrust coefficient (C-T), the power input coefficient (C-P) and the efficiency (eta) values are also obtained and linked with the flexibility, trailing edge motion and flow structures in the near-wake.