Robustness and Performance of Logarithm-Conformation Methods for Viscoelastic Flow Problems

Kurzfassung

Viscoelastic flow phenomena are being observed in several production processes of the plastics industry, like injection molding, compression molding, extrusion - to mention only a few. A priori simulations of such processes can help to significantly reduce development and production costs and improve the quality of the product. Nevertheless, simulations that consider viscoelastic stresses are very rarely performed in an industrial context due to the high complexity of the problem. When simulating viscoelastic flow problems, several challenges arise due to the introduction of a polymeric extra stress tensor in the momentum balance, which is described by a set of constitutive equations. Fattal and Kupferman have shown that, for a wide range of constitutive models like the Oldroyd-B model for example, there exists an equivalent representation for the matrix-logarithm of the conformation tensor. Since then, many benchmark tests have shown that log-conformation methods are more stable compared to the standard scheme and allow solutions that are beyond the limiting high Weissenberg numbers. Furthermore, several different derivations of log-conformation methods have been developed over the years. In this talk, we will demonstrate viscoelastic fluid simulations in a finite volume setting that are based on the open-source libraries OpenFOAM and RheoTool and have been computed on HPC systems. We will present stability and performance analyses for several different log-based evolution equations, compare their results, and discuss their pros and cons.