Discharge flow of granular media from rectangular silos: Role of an obstacle and modelling by an orifice at the corner

Abstract

We present an experimental study on the discharge flow of a granular media from a rectangular silo with a cylindrical obstacle placed above the outlet. As described in the literature, the presence of an obstacle decreases the flow rate, but the characteristic lengths to be chosen in the flow rate law are not known. To predict the flow rate we vary the obstacle diameter and vertical position, the outlet size and the particle diameter. However due to the large number of parameters we find that the characteristic length which controls the flow rate cannot be thoroughly defined. To model the effect of an obstacle on the flow rate we design a new configuration with an orifice at the corner of the silo. We study the two extreme cases (a bottom orifice at the wall and a lateral orifice) and we show that for the corner all the data are in between these two cases.