Fluctuations in apparent mass at the bottom of granular columns due to different arrangements

We report the fluctuations in apparent mass at the bottom of granular columns due to various configurations. It is found that the fluctuations decrease with the increase in the ratio of diameters of silo to grain. For the arrangement of different grain layers in a column, the higher fluctuations appear when the larger grains are stacked at the bottom layer while reversing the order of grain-layers leads to smaller fluctuations. We attribute this behavior to the randomness in the direction of frictional forces between the grains and the confining wall. Moreover, due to polydisperse media, the development of inhomogeneous force transmission in grains may cause this to happen.

► The fluctuations in apparent mass at the bottom of bi-layered granular columns.
► Fluctuations decrease with the increase in the ratios of silo to bead.
► The fluctuations in layered structures show strong correlation with stacked form.
► Randomness in the direction of wall-grain frictional force causes this to happen.
► Development of inhomogeneous force network in bidisperse grains is another cause.