Investigation of a Supersonic Jet from a Three-Stream Engine Nozzle

A rectangular single-expansion ramp nozzle (SERN) with an aft deck is used to model the exhaust from a three-stream engine. At the nozzle exit two unmixed streams exist. The first is assumed to be a perfectly mixed flow of core and fan streams operating at a nozzle pressure ratio of 4.25 and the second is the tertiary stream operating at a nozzle pressure ratio of 1.89. Above the aft deck, the two unmixed streams merge into the jet plume. Complementary simulation and experimental data were acquired for this geometry. Simulation data were obtained using the Naval Research Laboratory’s (NRL’s) jet engine noise reduction (JENRE) code. Experimental data were gathered in the Syracuse University anechoic chamber. The experimental and computational approaches provided similar results, giving confidence in both the simulation and the newly modified test facility. Using the newly acquired data the flow and acoustics were investigated and a trade study was performed, which found a potential “low noise” condition.