Simulation of viscoelastic stagnation flow

Abstract

A finite element simulation for the steady flow in a planar stagnation die was used to compute the velocity, pressure and stress fields. It is predicted that a region surrounds the stagnation point where the flow approximates a planar extension. This region is circular for the Newtonian liquid and becomes an ellipse for the Maxwell fluid. An isotropic point in the stress field is found for the Newtonian case as well as for the Maxwell fluid. Lubrication of the die wall, modeled as a finite slip, increases the size of extensional flow region by as much as 100%, while causing a migration of the isotropic stress point towards the die wall.