High Velocity Jet Noise Source Location and Reduction. Task 3 - Experimental Investigation of Suppression Principles. Volume II - Parametric Testing and Source Measurements
Abstract
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. A series of experimental tests was conducted to provide farfield acoustic data on 47 baseline and suppressor nozzle configurations and to provide aerodynamic nozzle performance on 18 of the configurations. Suppressor design parameters evaluated experimentally included: suppressor area ratio, radius ratio, flow management, inner stream geometry, element number and type, treated ejectors on multielement and unsuppressed inverted-coannualar-flow nozzles. Parametric testing established suppression levels for single and dual flow nozzles during static operation. Selective free- jet tests conducted on eight configurations were utilized to establish flight suppression levels for plug, chute, tube and hole nozzles. The aerodynamic performance test program illustrated that suppressed exhaust nozzles which incorporate elemental base areas as an integral part of the design are sensitive to external Mach number. In general suppressor element base drag was the most significant loss mechanism. This volume is part of the four volume set that constitutes the Task 3 final report.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1978
- Accession Number
- ADA094294
Entities
People
- E. J. Stringas
- J. F. Brausch
- Malcolm A Smith
- P. F. Scott
- W. S. Clapper
Organizations
- Federal Aviation Administration