GRAINS DISCHARGE EXPERIMENTS DUE TO A SUDDEN DEFLECTION OF AN ALASTIC GATE.*

Abstract.

Typically, the mass flow rate due to gravity of dry, non-cohesive granular material follows the Hagen-Beverloo formula, which is independent of the pressure due to the flow near the outlet orifice. When we introduce a flexible gate (elastic plate) at the exit with thickness, length and Young's modulus known, we observe in a rectangular silo that the mass flow rate depends on these quantities but not on pressure of the granular sample at the bottom. We show through experiments such a dependency when the deflection is sudden; the limit of large, but gentle deflections, is briefly discussed.