Sphere penetration by impact in a granular medium: A collisional process

TL;DR

This study uses two-dimensional simulations to demonstrate that collisional processes, rather than friction, primarily govern the penetration depth and stopping time of a sphere impacting a granular medium, aligning with experimental scaling laws.

Contribution

It reveals that collisional interactions are the main factor in granular impact penetration, challenging the traditional emphasis on frictional effects.

Findings

Simulations reproduce experimental scaling laws for penetration depth and stopping time.

Collisional processes are identified as the dominant mechanism in impact dynamics.

Frictional effects are secondary in the physics of granular impact penetration.

Abstract

The penetration by a gravity driven impact of a solid sphere into a granular medium is studied by two-dimensional simulations. The scaling laws observed experimentally for both the final penetration depth and the stopping time with the relevant physical parameters are here recovered numerically without the consideration of any solid friction. Collisional processes are thus found as essential in explaining the physics of the qualitatively observed phenomena whereas frictional processes can only be considered as secondary effects in the granular penetration by impact.