Verification of Calculations - an Overview of the Lisbon Workshop

This paper presents an overview of a Workshop dedicated to the Verification of Calculations held in Lisbon in October 2004. The Workshop aimed at evaluation of Computational Fluid Dynamics Uncertainty Estimators by comparing results of six groups on two twodimensional incompressible turbulent flows involving separated turbulent flows. Various numerical methods were represented, and calculations were done on smooth grids as well as deliberately poor grids in order to burden the Uncertainty Estimators. Even though local grid convergence was often non-monotone, the overall consensus evaluation was generally favorable for the Grid Convergence Index and the Least Squares version of it, as well as a monogrid Error Transport Equation method. Some residual doubts remain on the inter-group comparisons because of conceptual modelling differences and the possibility of undetected coding errors. These could be eliminated by the use of a realistic exact analytical solution produced by the Method of Manufactured Solutions, and the consensus favored this approach for a second Workshop on this theme.