We have performed experiments of axial segregation in the Oyama's drum. We have tested binary granular mixtures during very long times. The segregation patterns have been captured by a CCD camera and spatio-temporal graphs are created. We report the occurrence of instabilities which can last...

Determining the stability of granular matter piles is of basic concern in understanding many real-world phenomena (e.g. landslides, debris flow, and avalanches). While extensive literature exists dealing with the stability of mono-disperse systems, models for the dynamical behavior of...

A simple model for the dynamics of a granular system under tapping is studied. The model can be considered as a particularization for short taps of a more general one-dimensional lattice model with facilitated dynamics. The steady state reached by the system is discussed and the results are...

The couple stress of a three-dimensional vertical granular flow is investigated by means of a combined approach of discrete element method and averaging method. The velocity, mass density and couple stress are quantified under various flow conditions. The velocity and mass density profiles are...

We analyze a recently proposed continuous model for stress fields that develop in two-dimensional purely isostatic granular systems. We present a reformulation of the field equations, as a linear first-order hyperbolic system, and show that it is very convenient both for analysis and for...

Based on a recent model of shearing granular media we propose a new mechanism for slow dynamics. It consists of two main steps: A global optimization and a restructuring. We present numerical results of the model and its analytical treatment on the hierarchical lattice. A simplified local...

In this work we study the dissipative dynamics of a system of smooth hard spheres with a constant restitution coefficient and small number of particles in the homogeneous cooling regime. We focus on the velocity distribution from simulations in the molecular dynamics approach. The main goal of...

We investigate a one-dimensional rice-pile model. We show that the distribution of dissipated potential energy decays as a power law with an exponent α = 1.53. The system thus provides a one-dimensional example of self-organized criticality. Different driving conditions are examined in order to...

We apply a theoretical approach, originally introduced to describe aeolian ripples formation in sandy deserts, to the study of surface instability in ion-sputtered surfaces. The two phenomena are distinct by several orders of magnitudes and by several physical mechanisms, but they obey similar...

The granular gas dynamics under gravity is investigated by means of numerical simulation for the case of elastic collisions. Damped oscillations in the process of evolution to equilibrium are found and considered in detail. The nature of the oscillations is the deviation of the position of the...