ИСТИНА

The work is devoted to the experimental study of the jet installation noise by means of the azimuthal decomposition technique (ADT). Jet-wing interaction noise might become an important problem for modern and novel passenger aircrafts with high and ultra-high bypass turbofan engines. Elaboration of installation noise reduction techniques and development of theoretical and numerical models for this type of noise will benefit from additional information on the noise source physics. Azimuthal modal content of the acoustic field provides such additional information and allows identification of certain peculiarities of installation effect. The azimuthal mode amplitudes and directivities for jetwing interaction noise are measured and analyzed. Correlations between different azimuthal modes are measured and analyzed in several jet cross-sections where it was reasonable. Theoretical model capturing the main properties of the installation noise azimuthal components is proposed.