DLR Results from the Fourth AIAA Computational Fluid Dynamics Drag Prediction Workshop

A summary about the DLR, German Aerospace Center results from the fourth AIAA Computational Fluid Dynamics Drag Prediction Workshop is presented. Compared to the investigations in the previous three workshops, the latest workshop had a stronger focus on drag and trim drag predictions as well as pitching moment calculations. Therefore, the new Common Research Model developed by NASA’s Subsonic Fixed Wing Aerodynamics Technical Working Group and tested in NASA wind tunnels is used. It represents a state-of-the-art transonic transport aircraft configuration, and in contrast to the configurations previously taken, it includes an optional horizontal tailplane with three different tail settings. DLR has defined three objectives for its activities in the fourth drag prediction workshop. At first, investigations should identify solution accuracy and grid convergence behavior using prismatic element dominant grids for boundary-layer resolution in comparison to hexahedral element dominant grids. Second, the influence of turbulence models of increasing complexity is of interest regarding transonic pressure distributions and flow separations. Therefore, the one-equation turbulence model of Spalart and Allmaras, the two-equation Menter kω-shear-Stress-transport model, and the Speziale–Sarkar–Gatski/Launder–Reece–Rodi–ω Reynolds-stress model are applied. The third objective is to analyze what differences in the calculated pitching moments and horizontal tailplane trim angles can be expected for the Common Research Model with different horizontal tailplane settings when grids are regenerated for each setting or when they are deformed iteratively based on the grid for the initial setting. All investigations are performed with the grid generation software Solar and Centaur™ and the Reynolds-averaged Navier–Stokes solver TAU. Recently, selected experimental data have been released by NASA and are used here for comparisons.