Getting jammed in all directions: Dynamic shear jamming around a cylinder towed through a dense suspension

Abstract

Experimental results are presented from towing a cylinder through a dense suspension of cornstarch and sucrose-water. Focus is placed on the jamming fronts that exist in such systems. The literature has concentrated on the propagation of the jammed region under pushing, pulling or shearing conditions independently. How the different fronts interact and if the fronts are symmetric has remained unexplored. With the current setup, we are able to view a continuous, quasi-2D field around the cylinder. As such, a new way of generating jamming fronts is presented whereby pushing, pulling and shearing can be examined simultaneously. In agreement with previous studies, the front propagates roughly twice as fast in the longitudinal direction compared to the transverse direction, which is attributed to a single underlying onset strain, regardless of orientation from the cylinder. Although the jamming front shows nearly perfect transverse symmetry, there is small but repeatable longitudinal asymmetry. This is clearly evident in the velocity and strain field outside the jammed region, and also detectable in the front propagation and onset strain.