Onset of thermal convection in a horizontal layer of granular gas

The onset of thermal convection in a horizontal layer of granular gas was discussed. The Navier-Stokes granular hydrodynamics was employed for determining the threshold of thermal convection in an infinite horizontal layer of granular gas. A simple necessary condition for convection was formulated in terms of the Schwarzschild's criterion. The morphology of convection cells at the onset of convection was predicted.