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Onset of collective and cohesive motion.
It is found that this phase transition, in two space dimensions, is always discontinuous, including for the minimal model of Vicsek et al. for which a nontrivial critical point was previously advocated.
Large-scale finite-wavelength modulation within turbulent shear flows.
We show that turbulent "spirals" and "spots" observed in Taylor-Couette and plane Couette flow correspond to a turbulence-intensity modulated finite-wavelength pattern which in every respect fits the
Collective motion of self-propelled particles interacting without cohesion.
The onset of collective motion in Vicsek-style self-propelled particle models in two and three space dimensions is studied in detail and shown to be discontinuous (first-order-like), and the properties of the ordered, collectively moving phase are investigated.
Boltzmann and hydrodynamic description for self-propelled particles.
A homogeneous spontaneous motion emerges below a transition line in the noise-density plane, and is shown to be unstable against spatial perturbations, suggesting that more complicated structures should eventually appear.
Modeling collective motion: variations on the Vicsek model
We argue that the model introduced by Vicsek et al. in which self-propelled particles align locally with neighbors is, because of its simplicity, central to most studies of collective motion or
Taylor-like vortices in shear-banding flow of giant micelles.
Using flow visualizations in Couette geometry, it is demonstrated that vortices stacked along the vorticity direction develop concomitantly with interfacial undulations and are mainly localized in the induced band and their dynamics is fully correlated with that of the interface.
Elastic turbulence in shear banding wormlike micelles.
This work focuses on the high shear rate branch of the flow curve and shows that for sufficiently high Weissenberg numbers, this branch becomes unstable and is associated with a shear stress jump.
Interface dynamics in shear-banding flow of giant micelles
We report on the non trivial dynamics of the interface between shear-bands following the initiation of flow in a semi-dilute wormlike micellar system investigated using a combination of mechanical