ANALYSIS OF THE JET NOISE EMITTED BY AN AIRCRAFT DURING TAKE-OFF

Microphone array measurements with the DLR research aircraft ATRA flying in different configurations are presented with a focus on the analysis of sources in the engine jets. The free jets exiting the engine nozzles are large distributed source regions with locally and temporally fluctuating source distributions that evolve in the downstream direction. The source maps from the array data calculated with a deconvolution method for moving sources are divided into integration regions for the different noise sources of the engine and the free jet downstream. Frequency spectra of the integrated noise powers from the source regions of the engine inlets, the nozzles, and the jets for fly-overs in three different configurations with high engine speeds are presented and compared.