We study the spontaneous formation and evolution of small mounds in shallow shaken beds of fine glass beads. Experimentally, we find that these mounds coarsen over time, and like coarsening behaviors seen in other fields, the mean diameter of a mound grows as t1/3. We duplicate the phenomenon in a computational model in which grains flow down a surface at a rate proportional to its slope, and are subsequently re-entrained into valleys between mounds. This re-entrainment is conjectured to be due to air flow caused by separation between the bed and the container bottom during shaking. The model also produces coarsening that develops as t1/3.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Mechanics of Materials
- Physics and Astronomy(all)