Analysis of supersonic jet turbulence, fine-scale noise, and shock-associated noise from characteristic, bi-conic, faceted, and fluidic injection nozzles.

Abstract

Fine-scale mixing noise (FSMN) and broadband shock-associated noise (BBSAN) are the dominant components of supersonic jet noise in the sideline and upstream directions. We use the previously developed statistical FSMN and BBSAN models to compare the noise radiated from three different nozzles, i.e., a method of characteristics nozzle, a bi-conic nozzle, and a faceted nozzle at different operating conditions. A numerical sensitivity analysis is performed using the models by perturbing various model parameters and conditions such as nozzle pressure ratio (NPR), total temperature ratio, area ratio, and boundary layer thickness. We observed that FSMN is most sensitive to NPR and BBSAN is most sensitive to area ratio. We also examine the changes in source statistics and corresponding correlations of the radiated noise using the fluidic injection noise reduction technique. Noise reduction predictions relative to the baseline cases are compared at different operating conditions and similar reduction as the experimental measurements were obtained at over-expanded conditions. Finally, we analyze the noise source locations for both components of jet noise in the sideline direction. The trends predicted in this study increase understanding of the changes in source statistics and radiated noise for different nozzles over a range of operating conditions.