1 research outputs found
A Viscoelastic Catastrophe
We use a differential constitutive equation to model the flow of a
viscoelastic flow in a cross-slot 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 in-line
extensional rheometry