Particle exit distributions on a Galton board: Simulations and experiments

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

Viña del Mar, Chile

Workshop; Southern Workshop on Granular Materials 2006; 2006

Center for Advanced Interdisciplinary Research in Materials (CIMAT)

Here we present an experimental and numerical study concerning the problem of the passage of small disks through a Galton Board, i.e., a two dimensional array of equally spaced obstacles arranged to form a triangular lattice. This board is placed vertically in order to perform the real experiments and has lateral walls whose relative separation can be varied as wanted. Small disks are launched from above. They fall down because of gravity effects, colliding successively with the obstacles of the lattice and, eventually, with lateral walls. When they finally get the exit at the bottom of the board, they are collected in separate boxes 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.