Comparison study of drag prediction by structured and unstructured mesh method

Comparison study or computations for the Third AIAA Computational Fluid Dynamics Drag Prediction Workshop is performed on the DLR-F6 wing-body configurations with and without the wing-body fairing using the structured grid solver UPACS and unstructured grid solver TAS code. Grid convergence study at a fixed CL using a family of three difference density grids and the results by a sweep are discussed. The self-made multiblock structured grids and mixed-element unstructured grids are employed. Another participant's grid is also compared. Comparisons between the two codes are conducted using the same turbulence model. Moreover, the detailed comparisons are conducted on the grid topology at the corner of the wing-body junction, the turbulence models, and the thin-layer approximation in viscous terms using the multiblock structured grids. The reconstruction schemes to realize the second-order spatial accuracy are also compared on unstructured grids. By comparing the results, the sensitivity of drag prediction to these factors is discussed.