Silo flow and clogging in the presence of an obstacle

In a simple silo flow, the presence of an obstacle has been found to suppress clogging, but little systematic work has been done to test how general this is. By systematically varying the size and position of an obstacle, we find that generally an obstacle does suppress clogging, but in some cases may enhance clogging. By examining micro/mesoscale features of the flow we find that, even when comparing scenarios where clogging is suppressed, the reasons for the suppression may be different -- the intruder introduces both geometric and dynamic effects which compete differently.