M. Salikuddin

A coannular convergent nozzle with inner and outer stream diameters of 2.89" and 5.1", respectively, is tested by GEAE in its anechoic free-jet jet noise facility to provide an acoustic data base of coannular nozzles with convergent termination over a broad range of nozzle pressure ratios and total temperatures to NASA Langley and Lockheed Aeronautical Systems Company to enable the development of a prediction model for shock associated noise for coannular convergent nozzles. The test matrices cover a broad range of test conditions, that include normal and inverted velocity and temperature profiles. Since shock associated noise evaluation is the primary objective of this program, for all the tests, the nozzle pressure ratio for at least one stream is maintained supercritical. The data shows many complex characteristics compared to a single stream nozzle. The screech tones and broadband shockassociated noise humps are observed in the spectral distributions. The frequency of the spectral peak of these humps increases with increasing polar angles. Each spectrum is made up of several peaks and the peaks broaden with increasing polar angle. The turbulent jet mixing noise component is prominently observed at higher polar angles at lower frequencies, to the left of the screech tone. At these angles, we observe a well defined modulated feature and the modulation frequency seems to increase with polar angle. Flight simulation reduces the overall noise levels

First Joint CEAS/AIAA Aeroacoustics Conference, München, 1995

Conference Paper

englisch

21,0 x 29,7 cm, 13 Seiten

DGLR-Bericht, 1995, 1995-01, First Joint CEAS/AIAA Aeroacoustics Conference - Proceedings; S.99-111; 1995; Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V., Bonn

NA

aeroacoustics, noise measurement

Bibliothek

1995