Noise measurements from an ejector suppressor nozzle in the NASA Lewis 9- by 15-foot low speed wind tunnel

Acoustic results are presented on nozzle test experiments conducted in the NASA Lewis 9 x 15-ft anechoic wind tunnel on a 'hypermix' nozzle concept, a two-dimensional lobed mixer nozzle followed by a short ejector section designed to promote rapid mixing of the nozzle flow with the flow induced by the ejector. Acoustic and aerodyanmic measurements were carried out to determine the amount of ejector pumping, the degree of mixing, and the noise reduction achieved. Spectra from various nozzle configurations were compared to show the effect of the nozzle geometry on nozzle-alone noise, the benefit of adding an ejector to the mixer nozzles, and the effect of the ejector geometry on ejector/suppressor noise level.