Noise Control For Aircraft Engine Test Cells And Ground Run-Up Suppressors Volume 3:An Engineering Analysis Of Measurement Procedures And Of Design Data
Report Number: WADC TR 58-202 Volume 3
Author(s): Doelling, Norman, Bolt, Richard H.
Corporate Author(s): Bolt Beranek And Newman Inc.
Laboratory: Biomedical Laboratory
Date of Publication: 1961-11
Pages: 161
Contract: AF 33(616)-3335
DoD Project: 7210
DoD Task: 71708
Identifier: AD0404785
Abstract:
The physical aspects of noise control in aircraft engine test cells and ground run-up suppressors are reported. The measurement procedures and the noise reduction data that form a technical basis for many of the techniques and ideas presented in the other volumes are analyzed. Er rors arising from the measurement equipment, wide band frequency analysis, random variations of noise level in time and space, the use of arti ficial noise sources, variations in air flow con ditions and different measurement procedures are investigated to obtain an objective measure of the reliability of data obtained from an AF sponsored program of acoustical evaluations of test cells and ground run-up suppressors. Data on impervious barriers and noise control com ponents for air passages are analyzed. The per formance of a single wall barrier can be reliably estimated, but the large noise reductions ex pected from double wall barriers are seldom ob tained because of flanking paths. The perform ance of noise control components for air passages was found to differ significantly from that pre dicted by theory (first order modes, long treat ment).
Provenance: IIT
Author(s): Doelling, Norman, Bolt, Richard H.
Corporate Author(s): Bolt Beranek And Newman Inc.
Laboratory: Biomedical Laboratory
Date of Publication: 1961-11
Pages: 161
Contract: AF 33(616)-3335
DoD Project: 7210
DoD Task: 71708
Identifier: AD0404785
Abstract:
The physical aspects of noise control in aircraft engine test cells and ground run-up suppressors are reported. The measurement procedures and the noise reduction data that form a technical basis for many of the techniques and ideas presented in the other volumes are analyzed. Er rors arising from the measurement equipment, wide band frequency analysis, random variations of noise level in time and space, the use of arti ficial noise sources, variations in air flow con ditions and different measurement procedures are investigated to obtain an objective measure of the reliability of data obtained from an AF sponsored program of acoustical evaluations of test cells and ground run-up suppressors. Data on impervious barriers and noise control com ponents for air passages are analyzed. The per formance of a single wall barrier can be reliably estimated, but the large noise reductions ex pected from double wall barriers are seldom ob tained because of flanking paths. The perform ance of noise control components for air passages was found to differ significantly from that pre dicted by theory (first order modes, long treat ment).
Provenance: IIT