Figure 13. Contact numbers for three contact types (L-L, L-S and S-S)
for different mixtures.
The contact numbers for the three contact types for the different
mixtures are normalized and shown in Figure 14. The L-L and L-S contact
numbers are normalized by the number of large particles in the given
mixture, and the S-S contact number is normalized by the number of small
particles. From the perspective of normalized contact number, the L-S
contact is the dominant type of contact for the binary mixtures,
indicating that for the current particle size ratio of 4.5, the large
particles in the binary mixtures are surrounded by small particles
sticking to the surface. The normalized L-S contact number for the
binary mixtures ranges from 45 to 12 and decreases with increasing mass
fraction of large particles. The significant difference in normalized
L-S contact number for various composition indicates that different
composition has different contact structure. This is especially true for
the contact structure around the large particles, which may also affect
the motion of particles and contribute to the shear stress difference.