Modeling and simulation of bird flapping flight : control, wakes and formation by Victor COLOGNESI

For the degree of Doctor of Engineering Sciences and Technology

Birds have always been a source of inspiration for humans. From the record distances crossed by the bar-tailed godwit during its migrations, to swifts staying aloft continuously for up to ten months, they are capable of achievements that artificial devices are still far from reproducing. We still have a lot to learn from the flight of birds, and the unveiling of the mechanisms behind their efficiency could open the way to new levels of performances for our man-made air vehicles.

While many works have relied on observations and experimental measurements conducted on birds and have led us to a certain knowledge of their flight mechanisms, the present work builds upon the idea that reproducing bird flight in simulation can shed light on what makes them so efficient. Indeed, plain mimicry of the natural flight of birds does little toward the better understanding of its underlying principles whereas the numerical reproduction of the broad range of phenomena involved allows us to test various hypotheses.

In this thesis, we report on the development of a model for bird flapping flight. This model includes a representation of the wing skeleton and the main flight feathers, controllers aimed at the stabilization of flight and a faithful modeling of the wake behind a bird.

The model is applied to the study of the dynamics of a bird in controlled flight, the analysis of its wake and of the interactions between two birds flying in formation. In the results, we present predictions regarding the distribution of aerodynamic forces and the contributions to the flight power. We also analyze the structure of a bird wake, verifying hypotheses concerning the positioning of a bird flying behind another, and we simulate the formation flight of two birds, exploring the control strategies that stabilize the follower, and how its position affects the reduction in its flight power.

Jury members :

• Prof. Philippe Chatelain (UCLouvain), supervisor
• Prof. Renaud Ronsse (UCLouvain), supervisor
• Prof. Eric Deleersnijder (UCLouvain), chairperson
• Prof. Grégoire Winckelmans (UCLouvain), secretary
• Prof. Grigorios Dimitriadis (ULiège)
• Prof. Ben Parslew (Manchester University, UK)

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