High Velocity Jet Noise Source Location and Reduction Task 3. Experimental Investigaton of Suppression Principles Volume III. Suppressor Concepts Optimization

摘要

Experimental investigations were conducted of suppression principles, including developing an experimental data base, developing a better understanding of jet noise suppression principles, and formulating empirical methods for the acoustic design of jet noise suppressors. Acoustic scaling has been experimentally demonstrated, and five 'optimum' nozzles have been selected for subsequent anechoic free-jet testing. Several studies were conducted to attempt an optimization of suppressor concepts. Trade studies of performance versus suppression, aircraft integration studies, and development of a figure-of-merit method of analysis all make up the activities in this 'optimization' process. The end product of this effort was to design five nozzles for static and free-jet testing. Demonstration of acoustic scaling for several suppressor configurations was conducted to assure the adequacy of using scale-model results to project full-scale suppression levels. Full-scale data were obtained on several suppressor configurations using J79 and J85 engines. Scale-model data were obtained for these same configurations to allow comparison of scale-model and full-scale results.