Sonic Boom Velocity and Altitude Sensitivity Analysis of a Hypersonic Aircraft Concept

During the last decades there has been a renewed interest in the development of a new generation of supersonic aircraft for civil purposes with limited implications to the environment. However, the noise generated by supersonic aircraft during supersonic flight, commonly referred to as "sonic boom", still creates annoyance to community on the ground that prohibits supersonic overland flight. To prepare for the advent of a new generation of supersonic aircraft and to define new regulations for them, an increasing number of sonic boom studies is being published. This paper presents numerical simulations of the sonic boom of a hypersonic (Mach 5) aircraft concept during the full flight envelope, including a sensitivity analysis of the two parameters velocity and altitude. The extensive simulations characterize the sonic boom distribution on ground, which is usually referred to as “sonic boom carpet”, caused by the aircraft for different speeds between Mach 1.2 and Mach 5.0, and for two altitudes of 11.3 km and 28.0 km above sea level. Different loudness metrics were calculated for the different flight conditions, including PLdB, ISBAP and SEL related metrics. The simulation approach is divided into two main regions. This approach is well understood and was validated during the three NASA Sonic Boom Prediction Workshop held between 2014 and 2021: The dual approach consists of (1) a near-field domain computed with Computational Fluid Dynamics (CFD) using a hybrid mesh and a Fluent solver based on ROE-FDS numerical scheme, and (2) a far-field propagation algorithm based on ray tracing and a nonlinear, one-dimensional shock wave propagation algorithm (Augmented Burgers Equation). The results highlight the differences in sonic boom behavior and loudness metrics due to Mach number and altitude variation. The propagation results are compared with the ones given by NASA’s PCBoom software.