Grid Quality and Resolution Issues from the Drag Prediction Workshop Series

The drag prediction workshop series, held over the last six years and sponsored by the AIAA Applied Aerodynamics Committee, has been extremely useful in providing an assessment of the state of the art in computationally based aerodynamic drag prediction. An emerging consensus from the three-workshop series has been the identification of spatial discretization errors as a dominant error source in absolute as well as incremental drag prediction. This paper provides an overview of the collective experience from the workshop series regarding the effect of grid-related issues on overall drag prediction accuracy. Examples based on workshop results are used to illustrate the effect of grid resolution and grid quality on drag prediction, and grid convergence behavior is examined in detail. For fully attached flows, various accurate and successful workshop results are demonstrated, and anomalous behavior is identified for a number of cases involving substantial regions of separated flow. Based on collective workshop experiences, recommendations for improvements in mesh generation technology that have the potential to impact the state of the art of aerodynamic drag prediction are given. [PUBLICATION ABSTRACT]