Exit distribution function crossover in a Galton board

BENITO, J. G.; MEGLIO, G.; IPPOLITO, I.; RE, M.; VIDALES, A. M.

Granular Matter

Springer

Lugar: New York, U.S.A.; Año: 2007 vol. 9 p. 159 - 168

1434-5021

Here we present an experimental and numerical study concerning the problem of the influence of walls on a granular flow through obstacles. The system based on a Galton Board is a vertical bi-dimensional array of equally spaced obstacles arranged to form a triangular lattice. Lateral walls, whose relative separation can be varied, are set. Disks of equal diameters are launched at the top of the system. During the fall, the disks collide inelastically with the obstacles of the lattice and, eventually, with lateral walls. At the exit, at the bottom of the board, disks are collected in separate bins depending on their final horizontal positions. The aim of the present paper is to study the dependence of the exit distributions of small disks on the separation between the lateral walls of the board. We found that there exists a crossover from a Gaussian-like to a uniform-like behaviour when the separation between walls is less than a critical value. A systematic study of this crossover is performed through numerical simulations and the results are also approximated by a theoretical model of the problem.