Numerical analysis of impact processes of granular jets

TL;DR

This paper numerically investigates the rheology of three-dimensional granular jets during impact, reproducing experimental scattering patterns and analyzing the constitutive behavior, including effective friction and shear viscosity.

Contribution

It provides a numerical analysis of granular jet impact, reproduces experimental patterns, and discusses constitutive equations and rheological properties.

Findings

Reproduces experimental scattering patterns through simulation

Suggests zero yield stress is a natural assumption in the setup

Finds shear viscosity is not small, contrasting previous experimental suggestions

Abstract

The rheology of a three-dimensional granular jet during an impact is investigated numerically. The cone-like scattering pattern and the sheet-like pattern observed in an experiment [X. Cheng, et al. Phys. Rev. Lett. 99, 188001 (2007)] can be reproduced through our calculation. We discuss the constitutive equation for granular jet impact in terms of our simulation. From the analysis of an effective friction constant, which is the ratio between the shear stress and the pressure the assumption of the zero yield stress would be natural in our setup and the shear visocity is not small in contrast to the suggestion by the experiment.