Interactions Between Flocks and Obstacles

The collective behavior of interacting active particles has generated considerable interest in recent years. Many models for such behavior have been proposed, ranging from simple systems of discrete particles with ad hoc interaction rules to continuum models with assumed interaction potentials to complex, bio-inspired models of collective animal motion. But in almost all cases, the resulting emergent behavior is studied in isolated systems far from boundaries. In contrast, we present results from a computational study of a simple discrete flocking model in the presence of obstacles. We consider both the behavior of the system in restricted domains bounded by solid walls and the scattering of developed flocks off of stationary targets, and discuss discuss the relationship of our results to liquid and granular systems.