Hydrodynamics of a Granular Gas in a Heterogeneous Environment

Abstract

Abstract:We analyze the transport properties of a low density ensemble of identical macroscopic particles immersed in an active fluid. The particles are modeled as inelastic hard spheres (granular gas). The non-homogeneous active fluid is modeled by means of a non-uniform stochastic thermostat. The theoretical results are validated with a numerical solution of the corresponding the kinetic equation (direct simulation Monte Carlo method). We show a steady flow in the system that is accurately described by Navier-Stokes (NS) hydrodynamics, even for high inelasticity. Surprisingly, we find that the deviations from NS hydrodynamics for this flow are stronger as the inelasticity decreases. The active fluid action is modeled here with a non-uniform fluctuating volume force. This is a relevant result given that hydrodynamics of particles in complex environments, such as biological crowded environments, is still a question under intense debate.

Thermodynamics and Statistical Mechanics of Small Systems

“…In [14], the transport properties of a low-density granular gas immersed in an active fluid, modeled as a non-uniform stochastic thermostat, are investigated. Navier-Stokes hydrodynamic equations can describe the steady flow in the system, even for high inelasticity.…”

Effective equilibrium picture in the xy model with exponentially correlated noise

“…In Active Matter [13][14][15][16][17], recent works pointed out the importance of memory effects on the angular dynamics of Vicsek like models [18,19]. However, in the presence of memory effects, it is not possible to perform the usual coarse graining procedure to obtain hydrodynamic equations [14,18].…”