CORE ENGINE NOISE CONTROL PROGRAM. VOLUME I. IDENTIFICATION OF COMPONENT NOISE SOURCES

Abstract : The various noise sources constituting the core engine noise for turbofan engines were identified and rank ordered. An investigation was made to ascertain the generating mechanisms, controlling variables, means of identification, and the effect on engine design if reduction were required for each of eight core engine noise sources. The relative significance of the various noise sources was evaluated by predicting the noise contribution of the individual components by the methods derived during the course of the Core Engine Noise Control Program. The predictions were made for each of the three hypothetical cycles for bypass ratios of 4, 7, and 14, respectively, which were formulated to encompass a range of commercial aircraft powerplants.