Impact dynamics of granular jets with non-circular cross-sections

TL;DR

This study explores how granular jets with non-circular cross-sections behave upon impact, revealing liquid-like collective flow and anisotropic ejecta, with implications for understanding granular and plasma physics.

Contribution

It introduces the impact dynamics of non-circular granular jets, demonstrating anisotropic ejecta and liquid-like behavior, and draws analogies with quark-gluon plasma phenomena.

Findings

Anisotropic granular sheets form during impact.

Degree of anisotropy increases with aspect ratio.

Granular impact exhibits liquid-like collective flow.

Abstract

Using high-speed photography, we investigate two distinct regimes of the impact dynamics of granular jets with non-circular cross-sections. In the steady-state regime, we observe the formation of thin granular sheets with anisotropic shapes and show that the degree of anisotropy increases with the aspect ratio of the jet's cross-section. Our results illustrate the liquid-like behavior of granular materials during impact and demonstrate that a collective hydrodynamic flow emerges from strongly interacting discrete particles. We discuss the analogy between our experiments and those from the Relativistic Heavy Ion Collider (RHIC), where similar anisotropic ejecta from a quark-gluon plasma have been observed in heavy-ion impact.