Kenneth Desmond
     5th Year Graduate Student
Random Close Packing     Algorithm     Confined RCP     Ellipsoidal Packing    

I have developed an algorithm based on one proposed by Xu1 to generate random close packing of disks in 2D and spheres in 3D. The source code can be downloaded from here. The procedure involves slowly swelling and contracting disks or spheres with time until an rcp configuration is generated. We start by initializing a random arrangement of particles. Then we swell the disks until some of the disks overlap, at which point we apply an energy minimization technique to move the disks so they no longer overlap. If energy minimization produces a non-overlapping state then we begin swelling the particles again, otherwise we contract the particles until energy minimization will give a non-overlapping state. By repeating this swelling/contraction process while slowly decreasing the swelling/contracting rate an rcp configuration can be generated. Below is a movie demonstrating our algorithm along with a flow chart outlining the algorithm.

(1) N. Xu, J. Blawzdziewicz, and C. S. O’Hern, Phys Rev E 71, 061306 (2005)