An Eigenvalue-Free Log-Conformation Solver for Viscoelastic Simulations in OpenFOAM/rheoTool

  • Becker, Florian (German Aerospace Center (DLR))
  • Rauthmann, Katharina (German Aerospace Center (DLR))
  • Pauli, Lutz (MAGMA Gießereitechnologie GmbH)
  • Knechtges, Philipp (German Aerospace Center (DLR))

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High-fidelity simulations of injection molding are of considerable industrial interest, yet they remain challenging in practice because Maxwell-type viscoelastic constitutive models needed to capture the material response usually encounter the high-Weissenberg-number problem. In its standard formulation, the conformation tensor can lose positive definiteness due to numerical errors, leading to reduced robustness and, in the worst case, solver breakdown. The log-conformation approach introduced by Fattal and Kupferman largely mitigates this issue, however its proposed formulation relies on an – for PDEs unusual – eigenvalue decomposition of the evolving field. In this talk, we present an eigenvalue-free formulation for computing the log-conformation constitutive equation in 2D and 3D, and demonstrate a practical implementation in OpenFOAM/rheoTool.