Investigation of Active Noise Reduction of Jet Engine Runup Noise

摘要

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).