Dynamics and aerodynamics of flapping swimmers with dissimilar oscillating kinematics

Several objectives justify group travel for different species of birds and fishes. A first one is the protection against predators. A second one is the fluid interactions that each individual has with the others in its surroundings. However, it is less clear why groups of animals choose particular configurations to travel. Recent researches advance that, in a system with two pure plunging flapping swimmers, with a leader in front of a follower, the latter can find stable positions behind the leader. This in the case of two synchronized flapping swimmers, so with identical flapping motion, but also in the case where the follower has a flapping motion with different kinematic parameters. In particular, different amplitude, frequency and/or phase angle. This master thesis uses the computational fluid dynamics to study numerically the fluid interactions between two flapping swimmers in line in water. It is determined where such stable positions for the follower behind the leader occur, in function of the kinematics. Furthermore, the classical Prandtl lifting line theory is used on the follower to evaluate the forces it undergoes in the wake of the leader. It aims to provide an explanation of the convergence of the follower to these positions.