The drag on a vibrated intruder moving in the confined granular media

• Self-induced vibration obviously influences the drag force on the moving probe.
• Drag-velocity relationship exhibits different regimes under vibrating conditions.
• An intrinsic parameter of self-excited vibration is proposed.
• The criticality of this parameter is discussed based on a proposed phase diagram.
• The origination of a stable linear dependence of drag force is explored.

In this paper, we investigate the drag on an intruder moving in confined granular media based on a discrete element method when its self-induced vibration perpendicular to its moving direction occurs. The influence of vibrating parameters on its dynamical properties is mainly considered. With the enhancing intruder's vibration, we find that the dependence of drag force on its moving velocity exhibits different regimes and then a dimensionless acceleration is proposed as a more intrinsic vibrating parameter determining the drag-velocity relationship, which gradually changes from quadratic to linear with the increase of dimensionless acceleration. The criticality of this parameter is also discussed based on a proposed phase diagram. Finally, our simulating results suggest that, once the dimensionless acceleration exceeds its critical value from below, the evolution of force chains near the intruder exhibits a similar feature, which may account for a stable linear dependence of the drag force on its velocity.

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