Discharge rates of dry granular material from bins with lateral exit holes

In this work we have analyzed experimentally the mass flow rate, m⋙, of the lateral outflow of cohesionless sand beach and granulated sugar through circular orifices of diameter D and rectangular and triangular slots of hydraulic diameter D_H made in vertical walls of bins. Such experiments were also performed in order to determine the influence of the wall thickness of the bin, w. Geometrical and physical arguments are given to get a general correlation for m⋙, embracing both quantities, D (or D_H) and w. The angle of repose is also an important factor characterizing these gravity flows.