In this work, the Monte Carlo method (MC) was extended to simulate the pack
ing and segregation of particles subjected to a gravitational field and con
fined inside rigid walls. The method was used in systems containing spheres
inside cylinders. The calculation of void fraction profiles in both the ax
ial and radial directions was formulated, and some results are presented. I
n agreement with experimental data, the simulations show that the packed be
ds present structural ordering near the cylindrical walls up to a distance
of about 4 particle diameters. The simulations also indicate that the prese
nce of the cylindrical wall does not seem to have a strong effect on the gr
avitational segregation phenomenon.