Fifth Drag Prediction Workshop: Computational Fluid Dynamics Studies Carried Out at ONERA

This article presents the computational studies that have been performed at ONERA-The French Aerospace Lab in the context of the 5th AIAA Drag Prediction Workshop. A grid-convergence process and a buffet-onset study have been carried out using a Reynolds-averaged Navier-Stokes solver and far-field methods. In this work, the multiblock grids of the Common Research Model provided by the 5th AIAA Drag Prediction Workshop Committee are employed, and a new meshing strategy involving overset techniques and Cartesian grids is tested. All of these meshes are computed with the ONERA elsA code using the Spalart-Allmaras turbulence model and far-field drag analyses are performed with the ONERA ffd72 software. The grid-convergence study led with the common multiblock grids gives an extrapolated drag value close to 250 drag counts, which corresponds to the numerical median of all 5th AIAA Drag Prediction Workshop participants. The meshing approach using Cartesian grids also provides promising results. Comparisons with NASA wind-tunnel tests show reasonable discrepancies between computational fluid dynamics predictions and experimental drag measurements. The buffet-onset study completed with the medium common multiblock grid is aimed at investigating an angle-of-attack sweep at cruise Mach number. Global and local analyses combining near-field and far-field approaches are presented.