Towards accurate flow predictions using unstructured meshes

The 3rd AIAA Drag Prediction Workshop (DPW 3) showed a wide range of predictions using unstructured grid technology. At that time, Boeing’s BCFD unstructured flow solver lacked the accuracy of structured grid flow solvers at predicting absolute cruise drag numbers. Since the Workshop, efforts have focused on improving the accuracy of BCFD unstructured grid predictions by re-visiting the numerical discretization and paying careful attention to all aspects of the algorithm. Improvements in the cell gradient calculation, slope-limiter, viscous flux operator, and boundary conditions have lead to significant accuracy improvements. This is illustrated by updated predictions on the DLR F6 (DPW 3 configuration) where the latest simulations rival the accuracy obtained by the best industrial codes. I