Flow and clogging in a silo with an obstacle above the orifice

TL;DR

This study investigates how placing an obstacle above the outlet in a silo affects flow dynamics, clogging probability, and arch formation, revealing that obstacle position and outlet size significantly influence flow behavior and pressure reduction.

Contribution

The paper extends previous work by analyzing the impact of obstacle position across different outlet sizes and explores the relationship between flow rate, avalanche size, and flow fluctuations.

Findings

Obstacle presence reduces clogging probability.

Flow rate and avalanche size are not directly linked.

Obstacle position influences flow and arch geometry.

Abstract

In a recent paper [Zuriguel et al., Phys. Rev. Lett. 107, 278001 (2011)] it has been shown that the presence of an obstacle above the outlet can significatively reduce the clogging probability of granular matter pouring from a silo. The amount of this reduction strongly depends on the obstacle position. In this work, we present new measurements to analyze different outlet sizes, extending foregoing results and revealing that the effect of the obstacle is enhanced as the outlet size is increased. In addition, the effect of the obstacle position on the flow rate properties and in the geometrical features of arches is studied. These results reinforce previous evidence of the pressure reduction induced by the obstacle. In addition, it is shown how the mean avalanche size and the average flow rate are not necessarily linked. On the other hand, a close relationship is suggested between the mean avalanche size and the flow rate fluctuations.