Physics Letters A 242 (1998) 3261328 Phase boundaries in vertically vibrated granular materials

A boundary structure is observed in beds of vertically vibrated granular materials separating regions of opposite phase. This structure is investigated and it is identified as giving rise to both a global kink and hexagonal patterns. A global phase diagram of surface patterns on a vibrated bed is presented. c © 1998 Published by Elsevier Science B.V. In recent years, there has been a dramatic surge in interest in the behavior of granular materials. Of par-ticularly high profile has been the compelling work on vertical vibration and pattern formation. In beds of small grains, convection, heaping and surface pat-terning have been reported [113]. Among the most detailed investigations of the surface pattern charac-teristics of such systems is a set of reports on surface geometries categorizing the dynamics of shallow lay-ers of grains [416]. In this Letter, we report on a tran-sitional structure in the phase change between thes