Regulation of Elastic instability from non-Brownian Suspension

Viscoelastic fluid flows distinctly from the Newtionian liquid. When the shear rate is high, the flow elasticity cannot be relaxed. And secondary flows will emerge. This phenomenon is named elastic instability. In this experimental work, we combined different rheoflow visualization techniques to investigate the influence of finite volume fraction non-Brownian suspension on the elastic instability of visco-elastic shear flow. We found that, in the visco-elastic flow, suspension assembles to large ordered structures, even under a volume fraction far lower than the random close pack. Further, such structures will regulate the secondary flow, which suppresses higher-order modes of the secondary flow. This research highlights the connections between suspension structures and the elastic instabilities of a viscoelastic flow. It also provides a new method to phase separate particles from the liquid.