R.A. Burdisso, C.R. Fuller, S.A. Glegg

An analytical model is developed for active noise control (ANC) of tonal inlet noise from turbofan engines. An aeroacoustic model of the fan is used to determine the complex amplitude of the spinning acoustic modes. The control inputs are modeled as monopole acoustic sources located on the periphery of the engine inlet duct. The error sensors can be either far field microphones or distributed inlet pressure transducers mounted on the inlet wall. The optimum control inputs to the secondary sources are obtained by minimizing the sum of the error sensor mean-squared-values. These control inputs are then applied to the secondary sources to compute the controlled acoustic field. The main goal in using this model is to analytically explore the basic mechanisms and potential of this ANC technique in attenuating tonal inlet noise. The results show that for the case of far-field sensors the control mechanism is the duct modal re-structuring which yields a weak radiating source at the inlet opening. On the other hand, using inlet sensors the attenuation in radiated power is achieved by suppression of the significant radiating modes.

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.231-238; 1995; Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V., Bonn

NA

aeroacoustics

Bibliothek

1995