STUDY ON FINITE ELEMENT METHOD OF THE EXTRUDATE SWELL PROBLEM(Ⅱ)MAXWELL FLUID AND THE STREAMLINE ELEMENT SCHEME

An important improvement on the streamline element method proposed recently by Luo-Tanner is put forwardin this paper,making the method more suitable for handling differential-type constitutive equations and flow sin-guiarities.Instead of integrating the constitutive equations along the streamlines forming element boundaries,onecould integrate them along the streamlines passing through the Gauss points of the elements.By this way the diffi-culty of discontinuous velocity gradients on the element boundaries is circumvented and the stress singularity at theexit point is aUeviated.Moreover,the amount of computation is considerably reduced.It is found,by testing withthe extrudate swell problem of the Maxwell fluid,that more strict enforcement of the incompressibility constraintby adopting a discontinuous-pressure scheme,discussed in the part I of this paper,allows one to obtain solutions ofbetter quality and for higher Weissenberg numbers.