Collision of Dynamic Jamming Fronts in a Dense Suspension

TL;DR

This study investigates how two dynamic jamming fronts in a dense suspension collide, revealing the unexpected formation of an unjammed region within the jammed material, using advanced visualization and velocimetry techniques.

Contribution

It provides the first experimental observation of jamming front collisions and the resulting unjammed region in dense suspensions.

Findings

Collision creates an unjammed region inside the jammed suspension

Visualization and velocimetry reveal the dynamics of front interaction

Results challenge existing understanding of jamming front behavior

Abstract

Dynamic jamming is a phenomenon whereby a dense suspension switches from a fluid-like to a solid-like state when subjected to sufficient stress and deformation. Large enough systems show that this transition is accompanied by a distinct jamming front. We present an experimental study where two jamming fronts are created simultaneously using two cylinders moving in parallel. We focus our observations on the collision of the jammed regions when the two fronts meet. Surprisingly, our measurements, combining surface texture visualization and time-resolved particle image velocimetry, show the formation of an unjammed region contained within the otherwise jammed suspension.