Similarity Analysis of Jet Wing Interaction 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 with a Mach number range of 0.6 to 1.1. The experiment set-up consists of a flat plate placed in proximity to a jet. Installation effects cause low-frequency noise increase with respect to the isolated case, mainly occurring in the direction normal to the plate and upstream of the jet’s exit plane. Based on the similarity analysis of noise spectra, scaling laws are found for the far-field noise produced by different plate lengths and jet exit velocities. The sound intensity of the jet plate interaction noise scales with the third power of the jet velocity and fourth power of the turbulence length scale. And an effective Helmholtz number is proposed to replace Helmholtz number to normalize the jet plate inter action noise spectrum. Finally, a semi-empirical prediction model is proposed based on the similarity analysis. And the verification results show that the prediction model is capable of accurately predicting jet noise in a wide range of jet velocity and plate length.