title: Nonlinear analysis of the shearing instability in granular gases
abstract: It is known that a finite-size homogeneous granular fluid develops a hydrodynamiclike instability when dissipation crosses a threshold value. This instability is analyzed in terms of modified hydrodynamic equations: first, a source term is added to the energy equation which accounts for the energy dissipation at collisions and the phenomenological Fourier law is generalized according to previous results. Second, a rescaled time formalism is introduced that maps the homogeneous cooling state into a nonequilibrium steady state. A nonlinear stability analysis of the resulting equations is done which predicts the appearance of flow patterns. A stable modulation of density and temperature is produced that does not lead to clustering. Also a global decrease of the temperature is obtained, giving rise to a decrease of the collision frequency and dissipation rate. Good agreement with molecular dynamics simulations of inelastic hard disks is found for low dissipation.
authors.affiliation: CECAM, ENS-Lyon, 46 Allee d'Italie, 69007 Lyon, France.
authors.initials: R
authors.lastname: Soto
authors.initials: M
authors.lastname: Mareschal
authors.lastname: Malek Mansour M