Role of shape on the forces on an intruder moving through a dense granular medium

TL;DR

This study uses numerical simulations to explore how the shape of an intruder affects drag and lift forces in dense granular media, revealing shape-dependent force distributions and the influence of friction and velocity.

Contribution

It provides new insights into the role of shape and friction in force interactions during intruder movement through granular materials.

Findings

Drag force increases gradually with velocity for frictionless particles.

Frictional systems show a low-velocity constant drag regime.

Lift force varies strongly with shape at a given velocity.

Abstract

We use numerical simulation to investigate the effect an intruder's shape has on the drag and lift forces that it experiences while moving through a granular medium composed of polydisperse disks of mean diameter d. The intruder velocity,v, was varied from 0.1 \sqrt(dg) to 20 \sqrt(dg). For frictionless particles (\mu= 0.0)there is a gradual increase in drag force with increasing v, whereas for frictional systems (\mu= 0.1,0.5) a constant drag regime appears at low velocities. The drag force depends weakly on the shape of the object provided that the cross-section is same. The drag force depends linearly on the immersion depth, while there is very little variation in lift force with depth for certain shapes. The lift experienced by the object is a strong function of its shape at a given velocity. Shape has an effect on the distribution of contacts around the surface of the intruder which may result in a strong lift for certain shapes. We also show the force profiles around the intruder surface.