Impact of Atmospheric Turbulence on Typical Shaped Booms

Abstract

Accurate sonic boom prediction is crucial for low-boom supersonic civil transports (SST). In the real atmospheric environment, atmospheric turbulence randomly distorts the shape and energy distribution of sonic booms, posing significant challenges in assessing their intensity. Previous studies have focused primarily on N-waves, revealing that atmospheric turbulence can transform N-type waves into P-type and R-type waves. Facing the practical applications in the future, supersonic civil transports must be designed with low-boom methods to minimize their impact on the ground. Additionally, the focused sonic boom generated during supersonic maneuvering flight is another critical consideration. At this time, sonic boom signals warrant attention not only classical N-type wave, but also low-boom waveform such as flattop-wave and ramp-wave, as well as focused waveform such as U-wave. However, the impact of atmospheric turbulence on these shaped booms are not clear. The present work investigates the influence of atmospheric turbulence on shaped booms. Using high-order finite difference time domain methods and high-performance computing, we employed a three-dimensional augmented KZK sonic boom propagation model coupled with an atmospheric turbulence model to simulate the propagation and evolution of shaped booms in the atmospheric boundary layer (ABL). Flight experimental data from D-SEND\#1 project was used to validate the present models and numerical methods. Results indicate that atmospheric turbulence has a relatively small distortion on both ramp-wave and U-wave, which is more conducive to low-boom design for supersonic civil transports. Conversely, the atmospheric turbulence has a relatively large impact on distortion of both N-wave and flattop-wave.

Keywords: sonic boom, supersonic civil transport, atmospheric turbulence, atmospheric boundary layer