DPW-8/AePW-4 Buffet Working Group: An Overview of Mini Workshops 1 and 2

This manuscript presents the findings from the joint DPW-8/AePW-4 BuffetWorking Group regarding Test Case 1, focused on buffet conditions for the ONERA OAT15A supercritical airfoil. A total of ten angles of attack at both pre- and post-buffet onset conditions have been selected for freestream Mach and Reynolds numbers of M = 0.85 and Re = 3 × 10^6, respectively. The study is divided into steady and unsteady analyses. For steady simulations, significant scatter was observed in the results, highlighting the lack of grid convergence across different turbulence models and grid types. Different turbulence models showed significant deviations in aerodynamic coefficients, with a shock-wave predicted farther downstream than the experimental observations. Although unsteady simulations, including URANS and Hybrid RANS/LES models, provided improvements in predicting shock location and behavior, they still exhibited discrepancies in fluctuation amplitudes and locations. Test Case 1 has provided valuable lessons in numerical methods, computational resources, and collaborative efforts. As the Working Group prepares for Test Case 2 involving full-aircraft simulations, careful consideration of unsteady calculation costs, grid sensitivity studies, and time-integration setups will be crucial for achieving meaningful results.