HYDRODYNAMIC DESCRIPTION OF GRANULAR CONVECTION

We present a hydrodynamic model that captures the essence of granular dynamics in a vibrating bed. We carry out the linear stability analysi s and uncover the instability mechanism that leads to the appearance o f convective rolls via a supercritical bifurcation of a bouncing solut ion. We also explicitly determine the onset of convection as a functio n of control parameters and confirm our picture by numerical simulatio ns of the continuum equations.