A Computational Study on Avian Flapping Flight and the Influence of Feather Separation

Bird flight is an area of significant interest due to the utilization and control of unsteady aerodynamic effects via flapping. Although modern aerodynamics were originally inspired by bird flight, contemporary computational and experimental work associated with flapping flight focuses on insect flight. The purpose of the present paper is to improve the understanding of avian flight by investigating upstroke downstroke velocities, feather separation, and ultimately develop a nondimensional model to predict lift and drag forces for seagull flight. The variation in upstroke-downstroke velocities were found to decrease both lift and drag as the relative upstroke velocity increased, but significantly increased the lift:drag ratio for the same flight regime. Feather separation was found to increase lift with maximum lift at a separation angle of 25, while drag increased linearly. A set of nondimensional equations found were using regression analysis that can be used as a design tool to predict both lift and drag without expensive experiments or excessive computational processing requirements.