A hybrid numerical model based on finite-element and discrete-element methods was verified for modelling the flow of granular materials in silos or bins. Laboratory experiments involving gravity flow of soybean from a parallel wall bin with length-to-width ratio of three (state of plane strain) were carried out for different outlet widths. Computer simulations successfully matched most of the observed features of the physical tests. The results showed that the maximum wall pressure occurs near the top of the hopper in the transition region from parallel to convergent flow. The ratio of the dynamic pressure to the static pressure at the level of transition ranged from 2·5 to 3·6 depending upon the width of the outlet.