Caractérisation expérimentale du bruit au décollage du lanceur Ariane 5

Abstract
At lift-off, a launch vehicle has to withstand a severe acoustic environment, induced by rocket jet and its impingement on the launch pad, which may damage the payloads and equipment. An experimental analysis of the lift-off noise applied to the ARIANE 5 launch vehicle was performed by ONERA in FAUGA MAUZAC facilities, in 1992-1993. This campaign, conducted on the responsibility of AEROSPATIALE as Industrial Architect within the framework of a CNES contract, intended to characterize the launcher acoustic environment and to test water injection as a noise reduction mean. This paper shows the 0.05 scale model launch vehicle and launch pad, equipped with 132 microphones in the frequency range 20 - 2000 Hz at full scale, the coherence between the different kinds of measurements, the research of analytical models for correlation functions, the test results in terms of levels versus altitude, correlation functions and the best mean of water injection. In conclusion, this campaign has given us all the data necessary to estimate the vibroacoustic response of the ARIANE 5 launch vehicle at lift-off in the frequency range of interest 20 - 2000 Hz.