Collective motion of self-propelled particles without collision and fragmentation

In this paper, we propose a novel model to generate collective motion of self-propelled particles without collision and fragmentation by means of adjusting the absolute velocity instead of the constant speed used in the original Vicsek model. Interactions among particles are represented by the r-limited Delaunay graph to guarantee the locality of the model. The centroid of the Voronoi cell is set as a destination to scatter particles. The formation of the group is controlled by the surface tension generated by particles on the boundary. Without noise and periodic boundary, given a collision-free and cohesive configuration initially, the abundant types of collective motion will emerge from the local behaviors. Numerical simulations demonstrate that our model can produce rich behaviors such as crystallization, rotation, flocking and cluster with different combinations of two coefficients adjusting the amplitude of centering force and surface tension, respectively. Collisions among particles and fragmentations of the group do not appear.