K.K. Ahuja, J. Manes, K.C. Massey

The objective of this study was to evaluate the effects of splitter plates mounted longitudinally parallel to the centerline of a single rectangular nozzle on nozzle noise performance as a function of jet Mach number and lip thickness. A pair of splitter plates were mounted at the exit of a convergent rectangular nozzle. In addition to making farfield noise measurements in an anechoic chamber, the mixing characteristics of this arrangement were evaluated qualitatively through flow visualization. It was found that such an arrangement enhanced the mixing of the jet considerably and reduced the noise of the jet at supersonic conditions by as much as 10 dB at most polar angles. Thicker inserts produced larger reductions in noise. The noise reduction appeared to occur as a result of vigorous jet mixing produced by the vortex shedding introduced by the splitter inserts. The mixing appeared to be most prominent whenever there existed some form of vibration of the splitter plates. Substantial noise reductions were obtained on using an ejector in conjunction with the inserts. High intensity tones associated with the vortex shedding in the wake of the splitter plates were observed at the subsonic conditions. Broadband noise also increased significantly at the subsonic conditions. In fact, at certain subsonic conditions, Parkers resonance took place with such high levels that the splitter plates underwent serious structural failures.

First Joint CEAS/AIAA Aeroacoustics Conference, München, 1995

Conference Paper

englisch

21,0 x 29,7 cm, 8 Seiten

DGLR-Bericht, 1995, 1995-01, First Joint CEAS/AIAA Aeroacoustics Conference - Proceedings; S.123-130; 1995; Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V., Bonn

NA

aeroacoustics, noise measurement

Bibliothek

1995