LAUSR

Turbulence effects on low amplitude sonic booms are not currently well understood. In 2011, NASA funded an experiment to collect data using a large linear microphone array, consisting of 81 ground placed microphones spaced 125-feet apart, as a supersonic F-18B aircraft flew over the array. Most of the measurements were made during aircraft maneuvers designed to place a focus boom on the microphones. However, a few flights were straight and level passes of the aircraft over the array. Data from two of these level passes were used to estimate filter functions that describe the variation at each microphone relative to the mean response across the array. Two approaches were implemented, one is frequency domain and the second is time domain. The resulting filters can be applied to other non-turbulent boom waveforms to estimate the changes in either the spectrum or time domain signature due to the variations observed during these flights. Variation in loudness level both outdoors and indoors when these filters ...