PARTICLE-SIZE SEGREGATION BY SHAKING IN 2-DIMENSIONAL DISC PACKINGS

A two-dimensional model for particle size segregation by shaking has been developed and applied to a binary mixture of discs with radius ratio PHI. The simulation results can be understood in terms of a simple theoretical model that becomes exact in the limit PHI --> infinity. When a single large disc is imbedded in a regular packing of small discs, it is shown that segregation occurs only for values of PHI above a critical value phi, which depends on the angle of repose alpha and varies between 2.993 ... and 12 when alpha varies from 30-degrees to 60-degrees.