Flows from Bins: New Results - Selected Topics of Computational and Experimental Fluid Mechanics - page 155

Flows from Bins: New Results

D.A. Serrano, A. Medina, G. Ruíz Chavarría and F. Sanchez Silva

Abstract Gravity granular flows of cohesionless materials emerging from bottom
exits and from lateral exit holes, both in vertical bins, and from face walls in tilted
bins were modeled and measured. The models are based on continuum mechanics,
whereas friction and gravity are the main involved forces. Measurements of the
granular mass flow rates were obtained from temporal measurements of weights
by using force sensors. In vertical and tilted bins the face wall thicknesses were
considered in the governing correlations. Measurements are in good agreement with
the theoretical predictions.

1 Introduction

This article considers the granular counterpart of the Torricelli's theorem. Torricelli's
theorem is a theorem in fluid dynamics relating the speed of fluid flowing, under
the action of gravity, out of an opening to the height of fluid above the opening.
Torricelli's law states that the speed of efflux, v , of a fluid through a sharp-edged
hole at the bottom of a tank filled to a depth, h , is the same as the speed that a body
(in thi s cas e a drop of water) would acquire if falling freely from a height h , i.e.,
v = √ 2 gh , where g is the acceleration due to gravity (Fig. 1 ).