Purely-elastic flow instabilities

Condensed Matter lunchtime seminar

Purely-elastic flow instabilities

  • Event time: 1:00pm
  • Event date: 29th September 2008
  • Speaker: Rob Poole (University of Liverpool)
  • Location: Room 2511,

Event details

The flow of viscoelastic fluids, e.g. polymer solutions or melts, can often give rise to spectacularly different flow phenomena compared to {simple} Newtonian fluids (water or air). One such manifestation of these differences is that in microfluidic geometries viscoelastic fluid flows can become unstable and time dependent in simple geometries at flow rates much smaller than would arise in the equivalent flow of a Newtonian fluid (typically due to inertial instabilities). Such {purely-elastic} flow instabilities arise as the inherently small scale of microfluidic flows accentuates the viscoelastic behaviour observed: the small length scale simultaneously makes the Reynolds number small and the Deborah or Weissenberg numbers, which characterize the degree of elasticity in the flow, large. In this talk I will discuss how we have been able to model one such experimentally-observed instability. I will then go on to briefly examine a series of purely-elastic instabilities that we have discovered in related geometries and some recent experimental verification of one such truly a priori prediction.

This is a weekly series of informal talks given primarily by members of the soft condensed matter and statistical mechanics groups, but is also open to members of other groups and external visitors. The aim of the series is to promote discussion and learning of various topics at a level suitable to the broad background of the group. Everyone is welcome to attend..

Find out more about Condensed Matter lunchtime seminars.