Steady Flow Dynamics during Granular Impact

Abstract

We study experimentally and computationally the dynamics of granular flow during impacts, where intruders strike a collection of disks from above. In the regime where granular force dynamics are much more rapid than the intruder motion, we find that the particle flow near the intruder is proportional to the instantaneous intruder speed; it is essentially constant when normalized by that speed. The granular flow is nearly divergence-free and remains in balance with the intruder, despite the latter's rapid deceleration. Simulations indicate that this observation is insensitive to grain properties, which can be explained by the separation of time scales between intergrain force dynamics and intruder dynamics. Assuming there is a comparable separation of time scales, we expect our results are applicable to a broad class of dynamic or transient granular flows. Our results suggest that descriptions of static-in-time granular flows might be extended or modified to describe these dynamic flows. Additionally, we find that accurate grain-grain interactions are not necessary to correctly capture the granular flow in this regime.

6 pages, 5 figures

References in corpus (10)

• Unified force law for granular impact cratering
• Scaling and dynamics of sphere and disk impact into granular media
• Particle Scale Dynamics in Granular Impact
• Annular shear of cohesionless granular materials: from inertial to quasistatic regime
• Granular impact and the critical packing state
• Robophysical study of jumping dynamics on granular media
• Nonlinear Force Propagation during Granular Impact
• Granular Impact Model as an Energy-Depth Relation
• Experimental velocity fields and forces for a cylinder penetrating into a granular medium
• Low-speed Impact Simulations into Regolith in Support of Asteroid Sampling Mechanism Design I.: Comparison with 1-g Experiments

Cited by in corpus (12)

• The physics of sediment transport initiation, cessation, and entrainment across aeolian and fluvial environments
• Wet granular flow control through liquid induced cohesion
• Grain-scale Modeling and Splash Parametrization for Aeolian Sand Transport
• Hybrid continuum-discrete simulation of granular impact dynamics
• Granular Response to Impact: Topology of the Force Networks
• Power law scaling of early-stage forces during granular impact
• Bending transition in the penetration of a flexible intruder in a 2D dense granular medium
• Effect of two parallel intruders on net work during granular penetrations
• Force and Mass Dynamics in Non-Newtonian Suspensions
• Stagnant Zone Formation in a 2D Bed of Circular and Elongated Grains under Penetration
• Universality in quasi-2D granular shock fronts above an intruder
• Force on a sphere suspended in flowing granulate