Intruder penetration in a vibrated and sheared two-dimensional granular medium

In this work, a passive intruder is moving through a tilted quasi-two-dimensional vibrated and sheared granular medium of soft spherical particles. Driven by the gravitational forces produced because of the slight inclination of the system, the passive intruder moves and penetrates throughout the granular medium. The dynamics of the intruder and the dynamical and structural characteristics of the particles in the medium are both determined. For obtaining the dynamical properties, the mean squared displacement of the intruder and each particle in the medium were estimated. The structural changes in the media, which are the outcome of the motion of the intruder, were observed and analyzed. The radial distribution function and the six-fold bond orientational order parameter were used to structurally characterize the medium, both with and without intruder penetration. Based on the different experiments performed, it was found that the intruder's trajectories fall into regions of lesser order in the granular medium.