Evaluation of sonic booms measured in D-SEND#2 flight test

Japan Aerospace Exploration Agency (JAXA) conducted a supersonic flight test named D-SEND#2 to validate its low-boom technology. In the D-SEND#2 test, sonic booms generated by a scaled, unmanned test vehicle designed by applying JAXA’s low-boom concept were measured on and above the ground. Due to a unique flight profile, various types of sonic booms, including N-type and shaped waveforms, generated under different flight conditions were obtained. Although the measurements aloft were intended to avoid or weaken the effects of atmospheric turbulence near the ground on the sonic boom signatures, distortions of waveforms were observed even in the sonic boom data measured above the ground. Noise metrics are calculated for the sonic booms measured at different altitudes, and the effects of the atmospheric turbulence are evaluated. The measurements are also compared with numerical predictions.