Swarming of gliding rod-shaped bacteria

We study swarming in systems of anisotropic self-propelled particles
(which represent bacteria) interacting through volume exclusion. Through
simulations, we give numerical evidence of a transition to swarming. At
the same time, we show that clustering effects can be captured by a mean
field approach. We find that clustering is controlled by the particle
aspect ratio and the packing fraction. We report a transition from
unimodal to bimodal cluster size distribution which is triggered by a
critical aspect ratio. We show the critical aspect ratio is a function of
the packing fraction. The applicability of these finding to bacterial
swarming is discussed.