ABSTRACT

When equally sized and shaped particles are randomly packed, crystalline clustering regions become detectable even with the naked eye. However, when the particles are of different shapes and sizes, as in sand, it becomes harder to identify any order and pattern formation. A common modelling conjecture was to assume that densely packed sands are in an ‘ideal’ disordered state. The consequence of this assumption is that the only characteristic length that has to be considered microscopically is the grain size with no possibility allowed for the emergence of other geometrical length scales above the particle level. In this paper we demonstrate numerically that even in polysized assemblies, particles are self-organised resulting in pronounced internal correlation between the locations of the particles.