Numerical simulation and change in type in the developing flow of a nonlinear viscoelastic fluid
Developing flow in the entrance of a planar slit is considered. A general nonlinear constitutive equation is used which accurately represents measured viscometric properties of both low- and high-density polyethylene melts, and a finite element orthogonal collocation method is used to compute the developing velocity and stress profiles. The local elliptic-hyperbolic character of the flow is determined, and the conditions under which a local change in type, as well as the range of convergence of the solution, are identified in terms of characteristic Reynolds and Weissenberg numbers. The range of convergence of the solution for the two sets of melt properties is shown to be significantly different.
low- and high-density polyethylene melts
finite element orthogonal collocation method
local elliptic-hyperbolic character of the flow
scientific article; zbMATH DE number 4091003