Dual-stream jet noise test with internal mixer design variations for LTO noise of supersonic aircraft

Abstract

One of the challenges of designing future commercial supersonic aircraft is accurate prediction and reduction of landing and takeoff (LTO) noise. It is expected that jet noise is a dominant noise source during LTO. In the present study a small-scale acoustic jet noise test has been designed and performed. The model contains a dual-stream nozzle including an external plug and has a modular design to vary nozzle length and internal mixers designs. An acoustic test in an anechoic environment with a sideline microphone array has been performed for a range of nozzle pressure ratios. The effect of mixer and lobes and nozzle length on the jet noise characteristics has been evaluated. Finally, a comparison with semi-empirical predictions for fully mixed flows shows the need for fast prediction of internally mixed exhaust systems.