Transmission loss measurements using a scanned array nearfield acoustical holography system in an anechoic/reverberation facility. Part II. Comparison of transmission loss methods.

2011 ◽  
Vol 129 (4) ◽  
pp. 2492-2492
Author(s):  
Bernard J. Sklanka ◽  
Joel R. Tuss
Keyword(s):  
Transmission Loss ◽  
Acoustical Holography ◽  
Nearfield Acoustical Holography

scholarly journals Experimental noise source identification in a fuselage test environment based on nearfield acoustical holography

2021 ◽  
Author(s):  
S. Ungnad ◽  
D. Sachau ◽  
M. Wandel ◽  
C. Thomas
Keyword(s):  
Sound Pressure ◽  
Noise Exposure ◽  
Transmission Loss ◽  
Measurement Data ◽  
Sound Field ◽  
Sound Intensity ◽  
Measurement Procedure ◽  
Test Environment ◽  
Acoustical Holography ◽  
Nearfield Acoustical Holography

AbstractA major challenge in the subject of noise exposure in airplanes is to achieve a desired transmission loss of lightweight structures in the low-frequency range. To make use of appropriate noise reduction methods, identification of dominant acoustic sources is required. It is possible to determine noise sources by measuring the sound field quantity, sound pressure, as well as its gradient and calculating sound intensity by post-processing. Since such a measurement procedure entails a large amount of resources, alternatives need to be established. With nearfield acoustical holography in the 1980s, a method came into play which enabled engineers to inversely determine sources of sound by just measuring sound pressures at easily accessible locations in the hydrodynamic nearfield of sound-emitting structures. This article presents an application of nearfield acoustical holography in the aircraft fuselage model Acoustic Flight-Lab at the Center of Applied Aeronautical Research in Hamburg, Germany. The necessary sound pressure measurement takes one hour approximately and is carried out by a self-moving microphone frame. In result, one gets a complete picture of active sound intensity at cavity boundaries up to a frequency of 300 Hz. Results are compared to measurement data.

Sign in / Sign up

Export Citation Format

Share Document