Figure 2
From: Attractive particle interaction forces and packing density of fine glass powders

Numerical simulation of the powder packing.
The figure displays a packing of 6172 cohesionless spherical particles of size distribution shown in Fig. 1i. The box size is Lx = Ly = 0.3351 mm (periodic boundary conditions) and Lz = 4.2 mm. Figures a–c show snapshots at time (in milliseconds) 0, 20 and 140.