CORE ENGINE NOISE CONTROL PROGRAM. VOLUME II. IDENTIFICATION OF NOISE GENERATION AND SUPPRESSION MECHANISMS

The mechanisms of noise generation and suppression for the various core engine noise sources in turbofans were defined through a balanced analytical and experimental program. Model, component, and engine tests were used to substantiate the results of the analysis and to determine the basic noise generating parameters. The results were cast in a general form so as to be applicable to a wide variety of cycles, including future technology turbofan engines. Several suppression concepts were identified through analysis and through logical extension of experience with earlier programs on on high velocity jet noise and fan/compressor noise research. The suppression concepts were validated through model and component tests and through evaluation of available engine data.