Accession Number : ADA297840

Title :   An Investigation of Active Noise Reduction of Jet Engine Runup Noise.

Descriptive Note : Final rept. Jul 93-Oct 94,

Corporate Author : WYLE LABS ARLINGTON VA

Personal Author(s) : Gibson, Robert G. ; Stusnick, Eric ; Smith, Jerome P. ; Burdisso, Ricardo A. ; Fuller, Chris R.

PDF Url : ADA297840

Report Date : AUG 1995

Pagination or Media Count : 135

Abstract : Active Noise Reduction techniques are used in this study to attenuate low-frequency broadband noise from jet engine exhaust. The low-frequency sound radiation from aircraft engine runup operations can result in a noise or vibration problem in nearby communities, even when aircraft are in test facilities such as hush houses or engine test cells. Experimental results are presented for the active reduction of broadband exhaust noise from both a stationary, unsuppressed jet engine and a jet engine installed in a small-scale simulated hush house. The control method is the feedforward filtered-x LMS algorithm and is implemented for both single-input, single-output and multi-input, multi-output systems. One-third octave band attenuations of up to 15 dB are achieved at error microphone locations, and large areas of significant noise reduction surround the error microphone locations. The areas of attenuation generally agree with analytical predictions. (MM)

Descriptors :   *NOISE REDUCTION, *JET ENGINE NOISE, ALGORITHMS, VIBRATION, ACOUSTIC WAVES, MATHEMATICAL PREDICTION, BROADBAND, SOUND TRANSMISSION, ACOUSTIC ATTENUATION, MICROPHONES, LOW FREQUENCY, LOUDSPEAKERS, JET ENGINE EXHAUST, JET AIRCRAFT, EXHAUST SYSTEMS, FREQUENCY SHIFT, PHASE CONTROL.

Subject Categories : Acoustics
      Noise Pollution and Control

Distribution Statement : APPROVED FOR PUBLIC RELEASE