CFL3D, FUN3D, and NSU3D Contributions to the Fifth Drag Prediction Workshop

摘要

Results presented at the Fifth Drag Prediction Workshop using CFL3D, FUN3D, and NSU3D are described. These are calculations on the workshop-provided grids and drag-adapted grids. The NSU3D results have been updated to reflect an improvement to skin-friction calculation on skewed grids. FUN3D results generated after the workshop are included for custom participant-generated grids, as well as a grid from a previous workshop. Uniform grid refinement at the design condition shows a tight grouping in calculated drag, where the variation in the pressure component of drag is larger than the skin-friction component. At this design condition, a fine-grid drag value was predicted with a smaller drag ad joint adapted grid via tetrahedral adaption to a metric and mixed-element subdivision. The buffet study produced a larger variation than the design case, which is attributed to large differences in the predicted side-of-body separation extent. Various modeling and discretization approaches had a strong impact on predicted side-of-body separation. A summary of similar published studies is provided to place these observations in context. This large wing-root separation bubble was not observed in wind-tunnel tests, indicating that more work is necessary in modeling wing-root juncture flows to consistently predict experiments.