Patterns and collective behavior in granular media: Theoretical concepts

TLDR

Granular materials, common in everyday life, have been studied for centuries yet still lack a unified theoretical framework, with many contradictory models describing their collective behavior and pattern formation. This review surveys situations where nontrivial patterns arise in granular systems, distinguishes them from similar continuum‑fluid phenomena, and outlines general principles and models of pattern formation applicable to granular media. The authors apply general principles and models of pattern formation in complex systems to explain and predict pattern emergence in granular media.

Abstract

Granular materials are ubiquitous in our daily lives. While they have been the subject of intensive engineering research for centuries, in the last two decades granular matter has attracted significant attention from physicists. Yet despite major efforts by many groups, the theoretical description of granular systems remains largely a plethora of different, often contradictory concepts and approaches. Various theoretical models have emerged for describing the onset of collective behavior and pattern formation in granular matter. This review surveys a number of situations in which nontrivial patterns emerge in granular systems, elucidates important distinctions between these phenomena and similar ones occurring in continuum fluids, and describes general principles and models of pattern formation in complex systems that have been successfully applied to granular systems.