Improving the numerical stability of steady-state differential viscoelastic flow solvers in openfoam®

Abstract

This work reports the developments made in improving the numerical stability of the viscoelastic solvers available in the open-source finite volume computational library Open FO AM® . For this purpose, we modify the usual both-side diffusion (BSD) technique, using a new approach to discretize the explicit diffusion operator. Calculations performed with the new solver, for two benchmark 2D case studies of an upper-convected Maxwell (UCM) fluid, are presented and compared with literature results, namely the 4:1 planar contraction flow and the flow around a confined cylinder. In the 4:1 planar contraction flow, the corner vortex size predictions agree well with the literature, and a relative error below 5.3% is obtained for De ≤ 5. In the flow around a confined cylinder, the predictions of the drag coefficient on the cylinder are similar to reference data, with a relative error below 0.16% for De ≤ 0.9.