ACTIVE CONTROL OF EXHAUST NOISE FROM MILITARY JET ENGINE TEST FACILITIES

摘要

Active control of broadband exhaust noise from a full-scale test facility for military jet engines has been successfullydemonstrated at a USAF hush house. A single-input, single-output system is implemented to control noise in the10 to 50 Hz range, with an airstream modulator as the control source. One-third octave band attenuations of up to8 dB are achieved at the error microphone location. A large area of significant noise. reduction surrounds the errormicrophone location. At low frequencies where noise reduction is most important, noise. reduction is achieved overan area of at least 5,000 square meters.