Experimental research of installed jet noise

For deeper understanding of the mechanism of the jet wing interaction noise, and improving the current generation of aircraft noise prediction tools. An experimental study of jet installation effects is conducted in this paper by operating a cold jet at Mach number 0.9. And a 2-inch single stream nozzle under a NACA0012 airfoil without pylon and deflected-angle is here considered. Both H (the separation distance between the jet centerline and the chord line of the airfoil) and L (the distance between the jet nozzle and the leading edge of the airfoil) are varied and their effects on installed jet noise are investigated. Farfield noise measurements were made at various azimuth angles and 60Dj (nozzle diameter) from the jet exit. Through the analysis of experimental data of jet wing interaction noise, two main sources are identified; reflection by the wing (higher frequencies), and interaction between the jet and the wing (low frequencies). And the similarity analysis shows that the low frequency jet-wing interaction noise has good agreement with large scale similarity function. Furthermore, this similarity insight coupled with experimental data is suitable for developing and validating jet noise prediction methods that include the effects of jet wing interaction.