Tristability in viscoelastic flow past side-by-side microcylinders

TL;DR

This study investigates how viscoelastic flow around two side-by-side microcylinders exhibits tristability and bifurcations, revealing complex flow path selection influenced by flow rate and cylinder gap.

Contribution

It provides experimental insights into flow path tristability and bifurcations in viscoelastic microscale flows, linking single-object behavior to array dynamics.

Findings

Identification of symmetry-breaking bifurcations with increasing flow rate

Discovery of bi- and tristability regions in flow path selection

Influence of cylinder gap on flow bifurcation behavior

Abstract

Viscoelastic flows through microscale porous arrays exhibit complex path-selection and switching phenomena. However, understanding this process is limited by a lack of studies linking between a single object and large arrays. Here, we report experiments on viscoelastic flow past side-by-side microcylinders with variable intercylinder gap. With increasing flow rate, a sequence of two imperfect symmetry-breaking bifurcations forces selection of either one or two of the three possible flow paths around the cylinders. Tuning the gap length through the value where the first bifurcation becomes perfect reveals regions of bi and tristability in a dimensionless flow rate-gap length `phase' diagram.