Experiments on eccentric granular discharge from a quasi-two-dimensional silo

Abstract

A comprehensive experimental investigation has been made to study the flow behavior during the discharge of granular material through an orifice at the bottom of a two-dimensional rectangular silo with an emphasis on eccentric orifice position. Two different methods, the deformation of colored bands and digital particle image velocimetry have been used to investigate the flow field. Based on the dynamics during the discharge, the entire granular matrix can be divided into different regimes. The evolution of free surface exhibits a self-similarity of its contour. Though the dynamics of granular flow for any position of the orifice exhibits some general trends, eccentricity of the orifice position induces unique complexity in the flow behavior. The proximity of the orifice with the wall induces a noticeable slip on it. This wall slip has a profound effect on the velocity distribution of the vertical flowing region. The rate of discharge has been observed to increase with eccentricity of the orifice position. Further, a detailed analysis of the inclined flow region reveals a unique velocity distribution with three distinct zones and helps to understand the flow physics.