H. Sakaguchi et al., PLUGGING OF THE FLOW OF GRANULAR-MATERIALS DURING THE DISCHARGE FROM A SILO, International journal of modern physics b, 7(9-10), 1993, pp. 1949-1963
Laboratory experiments and numerical simulations were performed to fin
d the mechanism of the plugging during the gravitationally emptying a
silo. Some interesting results were given by this investigation : 1)Tw
o major slip lines can be seen symmetrically about a vertical midline
in the continuous flow, but particles flow only on a one-side slip lin
e was found at each moment; 2) At transition of the flow from one-side
to the other, two-side flows collided each other on a vertical midlin
e. And this collision possibly resulted in the formation of the arches
of granular materials; 3) In the special case for 2) when arches were
stable enough under certain geometrical condition the plugging of the
flow occurred. For computer simulation on this issue, the Discrete El
ement Method specifically taking into account of rolling friction effe
ct was used. Results of numerical simulations were in good agreement w
ith the experimental measures not only in the flow pattern but also in
the occurrence of the plugging.