Results 201 to 210 of about 9,983 (255)

Modal decomposition method for acoustic impedance testing in square ducts

The Journal of the Acoustical Society of America, 2006
Accurate duct acoustic propagation models are required to predict and reduce aircraft engine noise. These models ultimately rely on measurements of the acoustic impedance to characterize candidate engine nacelle liners. This research effort increases the frequency range of normal-incidence acoustic impedance testing in square ducts by extending the ...
Todd, Schultz   +2 more
openaire   +2 more sources

TEST METHOD TO DETERMINE THE ACOUSTIC PROPERTIES OF BUILDING MATERIAL BY USING MICROPHONE IMPEDANCE TUBE

Akustika, 2021
The paper discusses a simple and low-cost method to design four microphone impedance tube of measuring the acoustic properties of building materials. The acoustic properties of the material are defined by the reflection coefficient, absorption coefficient, and transmission coefficient.
Sourabh Dogra, Arpan Gupta
openaire   +1 more source

Modal decomposition method for high-frequency acoustic impedance testing

The Journal of the Acoustical Society of America, 2005
Accurate duct acoustic propagation models are required to characterize and reduce aircraft engine noise. These models ultimately rely on measurements of acoustic impedance for candidate materials used in engine nacelle liners. This paper seeks to increase the frequency range of acoustic impedance testing by extending the standard two-microphone method (
Todd Schultz   +2 more
openaire   +1 more source

Uncertainty Analysis of the Two-Microphone Method for Acoustical Impedance Testing

8th AIAA/CEAS Aeroacoustics Conference & Exhibit, 2002
This paper presents two methods for determining the experimental uncertainty of normal-incidence acoustic impedance measurements using the twomicrophone method (TMM). The first method is an analytical technique that extends standard first-order uncertainty methods to complex variables.
Todd Schultz   +3 more
openaire   +1 more source

Modal Decomposition Method for Acoustic Impedance Testing in Rectangular Ducts

44th AIAA Aerospace Sciences Meeting and Exhibit, 2006
Accurate duct acoustic propagation models are required to characterize and reduce aircraft engine noise. These models ultimately rely on measurements of acoustic impedance for candidate materials used in engine nacelle liners. This paper seeks to increase the frequency range of normal incidence acoustic impedance testing in square ducts by extending ...
Todd Schultz   +2 more
openaire   +1 more source

Comparison of the Two-Microphone Method and a Modal Decomposition Method for Acoustic Impedance Testing

12th AIAA/CEAS Aeroacoustics Conference (27th AIAA Aeroacoustics Conference), 2006
Accurate duct acoustic propagation models are required to predict and mitigate radiated aircraft engine noise. These models ultimately rely on acoustic impedance measurements to characterize candidate engine nacelle liner materials. This paper compares two different methods for normal incidence acoustic impedance testing: the two-microphone method (TMM)
Todd Schultz   +2 more
openaire   +1 more source

Experimental Test of the Acoustic-Impedance Model for Underwater Blast Wave Transmission through Plate Materials

Journal of Engineering Mechanics, 2017
AbstractPrevious work has shown that the acoustic-impedance model does not accurately predict blast wave transmission through plates of 10 different materials in air.
Elijah Courtney   +3 more
openaire   +1 more source

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