A Viscoelastic Catastrophe
Abstract
We use a differential constitutive equation to model the flow of a viscoelastic flow in a crossslot geometry, which is known to exhibit bistability above a critical flow rate. The novelty lies in two asymmetric modifications to the geometry, which causes a change in the bifurcation diagram such that one of the stable solutions becomes disconnected from the solution at low flow speeds. First we show that it is possible to mirror one of the modifications such that the system can be forced to the disconnected solution. Then we show that a slow decrease of the flow rate, can cause the system to go through a drastic change on a short time scale, also known as a catastrophe. The short time scale could lead to a precise and simple experimental measurement of the flow conditions at which the viscoelastic catastrophe occurs. Since the phenomena is intrinsically related to the extensional rheology of the fluid, we propose to exploit the phenomena for inline extensional rheometry.
 Publication:

arXiv eprints
 Pub Date:
 February 2018
 arXiv:
 arXiv:1802.05739
 Bibcode:
 2018arXiv180205739E
 Keywords:

 Physics  Fluid Dynamics;
 Condensed Matter  Soft Condensed Matter;
 Computer Science  Computational Engineering;
 Finance;
 and Science