Abstract：To study the effect of outlet dimension and size on flow pattern and horizontal wall pressure distribution in a silo during wall outlet discharge, a series of experimental studies on silos filled with glass beads were carried out. The results show that the flow region and static region exist and separate clearly during discharge. The horizontal wall pressures in the static region and the channel edge during discharge are much greater than those in the static storage state. With the proceeding of wall discharge, the materials height decreases, so is the wall pressure. The discharge patch factor is between 1.5 and 2.0 in the static region, and it can be much greater than 2.0 in the channel edge.

Keywords: wall dischargd silo; wall pressure; discharge patch pressure; flow pattern