Silo flow of soft particles in varying gravity

We present results of LAMMPS Molecular Dynamics simulations of 2D gravity-driven flows of ~30,000 soft uniform spheres through a vertical silo. We model the flow while varying both the gravitational field strength of the system (g) and the elastic modulus of the particles (E). We find that the empirical Beverloo equation captures the data adequately for many trials, but fails for extreme combinations of g and E. We additionally present results of velocity profiles, granular temperatures, and local rearrangements in these systems. We introduce a dimensionless combination of g, E, the density (ρ), and radius (r) of the spheres, which collapses these measurements.