Exit distribution function crossover in a Galton Board

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

GRANULAR MATTER

SPRINGER

Lugar: Berlin; Año: 2007 vol. 9 p. 159 - 168

1434-7636

Here we present an experimental andnumerical study concerning the problem of the influenceof walls on a granular flow through obstacles. The systembased on a Galton Board is a vertical bi-dimensionalarray of equally spaced obstacles arranged to form atriangular lattice. Lateral walls, whose relative separationcan be varied, are set. Disks of equal diameters arelaunched at the top of the system. During the fall, thedisks collide inelastically with the obstacles of the latticeand, eventually, with lateral walls. At the exit, atthe bottom of the board, disks are collected in separatebins depending on their final horizontal positions. Theaim of the present paper is to study the dependenceof the exit distributions of small disks on the separa-tion between the lateral walls of the board. We foundthat there exists a crossover from a Gaussian-like to auniform-like behaviour when the separation betweenwalls is less than a critical value. A systematic study ofthis crossover is performed through numerical simulationsand the results are also approximated by a theoreticalmodel of the problem.