Numerical simulation of moving free surface problems in polymer processingusing volume-of-fluid method

We have developed a numerical. algorithm based on 2D/3D finite element meth od for solving non-Newtonian fluid flow with the moving free surface encoun tered in polymer processing. The power law model is considered as a theolog ical constitutive equation. The standard Galerkin finite element formulatio n/penalty formulation are applied to discretize the governing equations, th e volume-of-fluid (VOF) scheme is used to track the moving free surface, an d the donor-acceptor model introduced by Hirt and Nichols is modified and i mplemented on FEM. We applied the numerical scheme to simulate fountain flo w and viscous buckling problems. For fountain flow, the numerical predictio n of this study is in good agreement with the experimental results of other investigators, For viscous buckling, both 2D and 3D numerical simulations show that the shear thinning effect retards buckling, As this algorithm is very effective in treating moving free surface problems and requires less m emory than previous algorithms, it may help solve challenging problems in p olymer processing such as transient viscoelastic flow simulations with movi ng free surfaces.