The motion of the container
is given by z = asin (ωt) where z is the vertical position, a is the
amplitude and ω=2f where f is the frequency. The frequency was
fixed at 10 Hz. The amplitude could be varied from 0 to 10mm. The
granular material consisted of glass spheres, with bulk static density
= (1440±10) kg/m3, sieved between 180 and 300mwoven
mesh sieves (the grain size distribution was measured to be roughly
Gaussian, with the peak diameter at 270m and standard deviation
of 50m). Grains were contained in a Plexiglas cell depicted
Fig. 3B, shaped as an U-tube with square cross-section1. Experiments
were done at atmospheric pressure. The total mass of grains
was (0.1244±0.0001) kg, capable of filling one of the branches of
the U-tube from bottom to top.