Stress-blended eddy simulation of the aerodynamic and aeroacoustic characteristics over 30P30N high-lift configuration

High-lift devices with deployed leading-edge slats and trailing-edge flaps are major contributors to airframe noise during aircraft approach and landing. This study presents a high-fidelity numerical investigation of the aerodynamic and aeroacoustic characteristics of a generic, unswept, 30P30N high-lift configuration under approach conditions (Mach number Ma=0.17, Reynolds number Rec=1.71×106 and angle of attack α=5.5∘). An advanced turbulence scale-resolving technique -- Stress-Blended Eddy Simulation (SBES), integrated with the Generalised k−ω (GEKO) model in the attached boundary-layer region is employed for the first time in this context. Aeroacoustic predictions are obtained using an impermeable-surface Ffowcs Williams-Hawkings (FW-H) formulation. The simulation reveals complex unsteady flow phenomena in the slat cove, including the formation of quasi-two-dimensional turbulent structures at the slat cusp, their transition to three-dimensional behaviour along the shear layer, impingement of the vortex shear layer on the slat’s lower surface and the development of a low-speed recirculation bubble in the cove. Shear layer interactions with the slat-trailing edge are identified as the dominant noise-generation mechanism within the present two-dimensional configuration, with additional contributions from trailing-edge shedding and wake-boundary-layer interactions. Surface pressure spectra exhibit both broadband components and narrow-band peaks. The SBES-GEKO approach demonstrates satisfactory agreement with existing experimental data across near-field and far-field aerodynamic and aeroacoustic metrics, indicating its feasibility and capability to capture the relevant flow physics and associated noise generation mechanisms. Compared with conventional DES/DDES approaches, the SBES-GEKO provides improved robustness of hybrid RANS-LES behaviour under grid refinement, mitigating grid-induced separation while maintaining controlled numerical dissipation. The method’s computational efficiency and fidelity make it a promising tool for future aerodynamic and aeroacoustic studies of complex high-lift configurations and, with appropriate validation, for extension to full-scale aircraft applications.