Stall Evolution of Transport Aircraft at Subsonic Flow Conditions

The onset of flow separation on a swept aircraft wing poses significant challenges for numerical modeling due to the complexity of transient aerodynamic phenomena. This study evaluates and validates numerical methods for simulating incipient stall and analyses the flow behavior on a commercial transport aircraft configuration. The findings provide valuable insights into stall development and wake characteristics, enhancing the understanding of incipient flow separation on aircraft wings. To achieve this, hybrid RANS/LES simulation approaches were validated against experimental data from two test cases. First, a wing section of the NACA 64(3)-418 airfoil was analyzed and compared with wind tunnel measurements. The validated models were then applied to the “NASA Common Research Model”, a representative commercial transport aircraft configuration, with simulation results compared to experimental data from the European Transonic Windtunnel. The simulations provide detailed insights into the flow at the wing at incipient stall and its impact on the wake. Flow statistics, spectral, and modal analyses identify key flow phenomena at different angles of attack, including separation and reattachment dynamics, vortex shedding, and stall-cell propagation. Additionally, the turbulent wake was found to influence the inflow towards the horizontal tailplane, leading to variations in tailplane lift and load fluctuations.