Accuracy of the Cell-Centered Grid Metric in the DLR TAU-Code

Abstract

The drag prediction accuracy of the current version of the cell-centered grid metric discretization in the edge-based flow solver TAU lags behind the accuracy of the cell-vertex grid metric on highly-skewed unstructured meshes. Inaccurate convective fluxes and gradients contributing to the turbulence sources are identified as the reasons for this accuracy degradation. Alternative approaches for cell-centered discretizations are presented and shown to lead to significant accuracy and robustness improvements. Recommendations are given to improve spatial discretization schemes for the cell-centered grid metric in an edge-based finite volume code.