We use molecular dynamics simulations to study the formation of surface wavesin vertically vibrated granular material. We find that horizontal movements ofparticles, which are essential for the formation of the waves, consist of twodistinct processes. First, the movements sharply increase while the particlesare colliding with a bottom plate, where the duration of the collisions is veryshort compared to the period of the vibration. Next, the movements graduallydecrease between the collisions, during which the particles move through thematerial. We also find that the horizontal velocity field after the collisionsis strongly correlated to the surface profile before the collisions.
展开▼
