Effects of perturbing a reference atmosphere on sonic boom propagation and metrics Free

There is substantial interest in the accurate noise prediction that ranges from sonic boom noise from conventional supersonic aircraft to low-boom noise (a sonic thump sound) from future aircraft designed for quiet flight. A carefully designed reference atmosphere was developed for comparing multiple sonic boom propagation programs. In the current work, that reference atmosphere was perturbed in a number of ways to assess the importance of each perturbation. The code PCBoom was used for this study, and the perturbations were for the temperature, humidity, and wind profiles. One result is that in the absence of winds, perturbing the temperature profile does not substantially affect the metrics on the ground, but perturbing the humidity profile does. [Work supported by the U.S. Federal Aviation Administration Office of Environment and Energy through ASCENT, the FAA Center of Excellence for Alternative Jet Fuels and the Environment, Project 41 through FAA Award No. 13-C-AJFE-PSU under the supervision of Sandy Liu. Any opinions, findings, conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the FAA.]