Fluid-structure interaction of a bio-inspired passively deployable flap for lift enhancement

Covert-feathers-inspired passive flow control is beneficial for aerodynamic performance at post-stall angles of attack. However, most studies model covert feathers as a rigidly attached or a freely moving flap on a wing. The performance of a flap mounted via a torsional spring, emblematic to the finite stiffness of bird feathers, has remained unexplored. We simulate strongly coupled fluid-structure interactions of flow past a stationary airfoil with a passively deployable, torsionally mounted flap on the suction surface. We then perform a parametric study and an in-depth analysis of the dominant flow features that affect performance.