Numerical study of sonic boom propagation through atmospheric turbulence using open data of weather research and forecasting

Sonic boom noise is a major issue to be addressed for the realization of supersonic transport, and has therefore attracted considerable attention among stakeholders as well as researchers. In particular, the deformation of waveforms and changes in noise levels due to atmospheric turbulence have been studied from the viewpoint of assessing annoyance and certification standards. Atmospheric turbulence conditions vary depending on the environmental factors (e.g. region, season, time), and it is essentially a chaotic phenomenon; therefore, statistical evaluation is necessary to understand its effect. Although many studies on the effects of atmospheric turbulence on sonic booms have been conducted, few studies have investigated realistic trends of atmospheric turbulence. In this study, numerical analysis of sonic boom propagation considering atmospheric turbulence is performed for C609, an early type of NASA's X-59 Low-Boom Flight Demonstrator. The model equation for propagation is heterogeneous one-way approximation for the resolution of diffraction (HOWARD) and the Wilson and Ostashev model is chosen to define the atmospheric turbulence spectra. The parameters characterizing the atmospheric turbulence are set based on publicly available datasets of weather research and forecasting simulation. The sonic boom waveforms obtained by the numerical simulations and their noise level variations are statistically processed and evaluated.