Full-scale rocket motor acoustic tests and comparisons with models: Revisiting the empirical curves

Development of the next-generation space flight vehicles has prompted a renewed focus on rocket sound source characterization and near-field propagation modeling. Improved measurements of the noise near the rocket plume are critical for direct determination of the noise environment. They are also crucial in providing inputs to empirical models and in validating computational aeroacoustics models. NASA’s SP 8072 acoustic load prediction model is a widely used method for predicting liftoff acoustics. SP-8072 implements two Distributed Source Methods (DSM-1 and DSM-2), which predict the loading as the sum of the radiated field from each source distributed along the plume. The prediction model depends largely on empirical curve fits computed from historical data to determine the source power and frequency content at distances along the plume. Preliminary results from measurements of a static horizontal firing of Alliant Techsystems Orion 50S XLG performed in Promontory, UT are analyzed with respect to the his...