Scaling behaviour in size segregation (”Brazil Nuts”)

2014 Using a previously introduced Monte Carlo method, due to Rosato, Prinz, Strandburg and Swendsen, we carry out in two dimensions numerical studies of size segregation, a phenomenon which occurs when a granular medium made of particles of different sizes is shaken. We propose a new scaling law relating the segregation velocity 03C5 to the amplitude of shaking A and to the ratio R of the diameters of the small disks to the large disks. ForA larger than a critical amplitude Ac, a scaling law holds: 03C5 ~ (R2 1)03B1 f ((A -Ac) (R2-1)z) where 03B1 and z are exponents. Tome 51 NOS ler MARS 1990 1 Phys. France 51 (1990) 369-373 ler MARS 1990, PAGE Classification PhysicsAbstracts 46.10 02.70 81.20E Size segregation is a phenomenon which occurs when a box containing a powder made of particles of différent sizes is subject to some vibration. Upon shaking, the larger particles tend to rise to the top. This phenomenon seems to depend mainly on geometrical factors such as the size of the particles and the way the box is shaken, and depends little on other factors such as the différence in the density of the particles for example. This has led Rosato et al. [l, 2] to study a simple idealized two-dimensional case where a large disk is placed on the bottom of a box containing many small hard disks. Rather than solving the exact mechanical equations of motion like in a molecular dynamics simulation, a Monte Carlo method is used [3]. We first recall their method and indicate a few modifications we made. Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphys:01990005105036900