Effects of turbulence modeling on sonic boom loudness predictions from near-field simulations

This study investigates the influence of turbulence modeling on the near-field simulation and subsequent ground-level loudness prediction of sonic booms generated by a Supersonic Business Jet (SBJ). While inviscid simulations based on the Euler equations offer computational efficiency, they neglect boundary layer effects and may fail to accurately capture shock–boundary layer interactions that significantly influence shock strength and positioning. To assess the impact of turbulence modeling on sonic boom predictions, Reynolds-Averaged Navier–Stokes (RANS) simulations employing three turbulence models—k–ω, k–ε, and Spalart–Allmaras—are compared against Euler-based results. Computational grids adhere to the best practices established by the NASA Sonic Boom Prediction Workshop (2014–2020). The resulting near-field pressure signatures are propagated through four atmospheric profiles: the International Standard Atmosphere (ISA) and three measured realistic profiles. Ground-level waveforms are then evaluated using several loudness metrics, including Perceived Loudness Level (PLdB), ISBAP, and A–E weighted Sound Exposure Levels (SEL). The findings highlight how turbulence modeling affects the predicted loudness of sonic booms, providing guidance for balancing computational cost and physical accuracy in preliminary design and environmental impact assessments.