Airbus, ONERA, and DLR results from the Second AIAA Drag Prediction Workshop

The results from DLR, German Aerospace Center, Airbus, and ONERA from the Second AIAA CFD Drag Prediction Workshop are presented. The lift, drag, and pitching moments are calculated for the DLR-F6 configuration at transonic flow conditions by solving the Reynolds-averaged Navier--Stokes equations on structured as well as on unstructured, hybrid grids. First, the drag is computed with the standard near-field method by integrating the surface pressure forces and shear stresses and second by a drag breakdown into its physical components, such as viscous, wave, and induced drag, by applying a far-field method. The influence of the grid is investigated, and the results are compared to experimental data. For all cases a slightly smaller angle of incidence is required in the computations as compared to the experiments to obtain the same lift coefficient. The drag polars and the engine installation drag can be computed accurately, but significant deviations exist for the pitching moments as a result of an underestimation of the flow separation at the trailing edge of the upper wing upper. Comparing the far-field drag breakdown results for structured and unstructured solution methods shows that viscous and wave drag are computed nearly identical. The far-field method gives a better understanding of the sources of drag and offers a substantial benefit for aerodynamic design.