The influence of flow pattern and hopper angle on static and dynamic pressures in slender silos

This paper focuses on the influence of flow pattern and hopper angle (beta) on static and dynamic pressures in slender silos. The results were obtained using a test station developed by the authors, consisting of a silo (6 m high and 0.7 m internal diameter). Maize was used to generate the pressures. Five different hopper angles were tested by filling, static phase followed by complete silo discharge. Results are reported for pressure and flow analyses, and show that hopper angle influences normal pressures on the silo wall; Silos with transition flow do not have a concrete pattern of distribution of thrusts; pressure values are proportional to the variation of the hopper angle; and internal shear zones vary according to hopper angle, completely modifying the behaviour of static and dynamic pressures. Friction pressure and lateral pressure ratio values exceeded those calculated by the Eurocode 1, part 4.