Spectral element predictions of die-swell for Oldroyd-B fluids

This paper is concerned with two dimensional numerical simulations of plane extrusion of a viscoelastic fluid. The fluid is modelled using the Oldroyd-B and UCM constitutive equations. The problem is discretized using the spectral element method and the free surface is evolved using a Arbitrary Lagrangian Eulerian (ALE) technique. Numerical simulations are performed over an wide range of parameters. The influence of Weissenberg number and viscosity ratio on the swelling ratio and exit pressure loss are investigated and comparisons with previous results in the literature are presented. The range of validity of Tanner’s theory is investigated.