ABSTRACT
A disordered, two-dimensional assembly of identical, frictional, inelastic spheres self-organizes when appropriately shaken under the influence of gravity. The spheres form subassemblies of hexagonal packing, but with differing orientations, and continued shaking causes the larger assemblies to grow at the expense of smaller ones. This behavior is reminiscent of grain formation and coarsening in solid-state. The subassemblies are referred to as grains that are separated by relatively sharp grain boundaries. We create an assembly of a large parent grain surrounding a single, circular, internal grain to study the way in which such internal grains shrink. In as much as it is unclear what underlying micro-mechanisms drive the motion of these interfaces, we have undertaken both experimental and numerical investigations to quantify the kinetics of such grain boundary motion in non-cohesive dissipative granular media. The results are compared with the curvature driven solidification of solid-state systems.
