Harmonic Patterns in Fine Granular Vibrated Beds

Deep beds of fine grains vibrated at frequencies ranging from 10 to 100 Hz and over accelerations ranging from 1 to 14 times gravity spontaneously generate intricate surface patterns. Similarly to shallow beds, stripes, closed cells and labyrinthine patterns are found. In addition, we observe traveling waves, 'cannibalizing' cells and other behaviors that are both unexpected and remain unexplained. All of these patterns vary spatiotemporally, and unlike shallow bed patterns, are harmonic in that they change little from one vibration cycle to the next ( pdf reprint here).

Low frequency parameter space High frequency parameter space mpg movie of traveling surface waves on flat bed mpg movie of counterstreaming stripes on heaped bed <-     mpg movie of oozing patterns gif movie of model in progress