The role of muscular fatigue in position swaps during collective bird migration

This thesis is part of the RevealFlight Project. This project aims to understand the efficiency optimization mechanisms deployed by biological flyers through the study of the aerodynamics, mechanics and control laws of birds. In particular, this work focuses on the role of muscular fatigue in position swaps during collective bird migration. In the first place, the aerodynamics of a bird is examined in order to understand how migratory birds can take advantage of the upwash created by the bird in front of him. However, muscles cannot work all the time with the same efficiency. The three-compartment muscle fatigue model sheds light on the principle of endurance time, time before a muscle feels fatigued. A simple muscle model is then presented in order to simulate the distribution of the kinematics and dynamics of a bird into its passive and active elements. Finally, these models are put together so that the dynamics and kinematics of a bird can be simulated in order to obtain the endurance time of a bird. The impact of the velocity on the endurance time of a bird is analyzed as well as the difference between birds flying alone and birds flying in a flock and taking advantage of the upwash region.