Abstract
The modified singular/decoupled finite element method for the die-swell flow simulations of viscoelastic fluids was investigated. The special r^<-0.5> type singular elements (where r denotes the distance from singularity) in a small core region around the singular point have been applied for the elastic stress and pressure fields, and the special r^<0.5> type singular elements for the velocity field; and we have intentionally removed all of nodal points from the singularity. When discretizing the constitutive equation, the "1x2 subelement scheme" was introduced to the elastic stress in the singular element region, associated with 8 nodal special shape functions, i.e., the special r^<-0.5> type shape functions in the radial direction and bilinear shape functions in the azimuthal direction. It was found that the modified singular FEM yielded the more smoothed and rational asymptotic behavior in the vicinity of the singular point than the previous singular FEM.
