Implementation of Acoustic Blankets to the VLS Fairing - A Sensitivity Analysis Using SEA

During lift-off, launchers are submitted to severe acoustic loads, generated by the boosters' combustion. Typical overall sound pressure level (OSPL) values are estimated, at the upper parts, within 140-160 dB. Strategies to reduce the acoustic energy inside fairings, like the implementation of blankets, have been developed by the aerospace industry. SEA is a well known technique for high-frequency prediction analysis. A fluid-structure SEA model was generated in view of assessing the influence of the acoustic blankets in SPL attenuations inside the VLS fairing. Such materials and respective Biot's parameters were accounted to simulate the Noise Control Treatments (NCT) of the fairing to yield the inner cavity acoustic responses. This work presents a sensitivity analysis for the implementation of acoustic blankets to the VLS fairing in view of having acceptable SPL inside the acoustic cavity of the fairing. Comparisons between different acoustic responses are done and finally, the use of other attenuation techniques is recommended.