Dynamics of a grain on a sandpile model

摘要: The dynamics of a macroscopic grain rolling on an inclined plane composed fixed identical grains is investigated both experimentally and theoretically. As real sand, the system exhibits hysteretic transition between static dynamical states: for angles smaller than w d , roller always stops, larger s it spontaneously starts down. But can be either at rest or in motion with constant velocity. It shown that limit velocity given by equilibrium gravity driving dissipation shocks. Moreover, rough acts as periodic potential trap whose width depth decrease when angle increased: corresponds to which disappears; sufficient escape from trap. Finally, continuous description force globally acting proposed, preserves this behavior.