In this study, three values were used for the particle-wall friction coefficient, mw ¼ 0.1, 0.3 and 0.5. The particle stiffness was set to kn ¼ 1 104 N m1, the particle-particle friction coefficient was set at mp ¼ 0.3 and the damping ratio at x ¼ 0.5
In this study, three values were used for the particle-wallfriction coefficient, mw ¼ 0.1, 0.3 and 0.5. The particle stiffnesswas set to kn ¼ 1 104 N m1, the particle-particle frictioncoefficient was set at mp ¼ 0.3 and the damping ratio atx ¼ 0.5