The Scientist in the Sandbox: Complexity and Dynamics in Granular Flow

Abstract

Granular materials exhibit a rich variety of dynamical behavior, much of which is poorly understood. Fractal-like stress chains, convection, a variety of wave dynamics, including waves which resemble capillary waves, and fractional Brownian motion provide examples. Although granular materials consist of collections of interacting particles, there are important differences between the dynamics of a collections of grains and the dynamics of a collections of molecules; in particular, the ergodic hypothesis is generally invalid for granular materials, so that ordinary statistical physics does not apply. Nonlinear Dynamics, Mathematics, Molecular Dynamics, and Condensed Matter Physics as well as traditional Engineering fields have all contributed to recent insights for these phenomena.