Mass flow rate of granular material in silos with lateral exit holes

In this work we have analyzed experimentally the mass flow rate, m', of the lateral outflow of cohesionless granular material through circular orifices of diameter D and rectangular and triangular slots of hydraulic diameter D$_{\mathrm{H}}$ made in vertical walls of bins. Experiments were made in order to determine also 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 (D$_{\mathrm{H}})$ and w. The angle of repose is also an important factor characterizing these flows.