Results 71 to 80 of about 45,161 (201)

Modelling the Acoustic Properties of Baffles Made of Porous and Fibrous Materials

Archives of Acoustics
The research described in the article addresses the problem of measurement, prediction and practical use of the acoustic properties of materials determined in an impedance tube.
Krzysztof KOSAŁA
doaj   +1 more source

Investigation of Liner Axial Displacement in a Complex Acoustic Environment [PDF]

This paper investigates the effects of axial liner displacement on modal attenuation and scattering. Tests are conducted with a uniform liner mounted in the NASA Langley Curved Duct Test Rig, with a multimode source at flow conditions of Mach 0.0 and 0.3.
Brown, M. C., Jones, M. G., Nark, D. M.
core   +1 more source

Random and systematic measurement errors in acoustic impedance as determined by the transmission line method [PDF]

The effect of random and systematic errors associated with the measurement of normal incidence acoustic impedance in a zero-mean-flow environment was investigated by the transmission line method.
Parrott, T. L., Smith, C. D.
core   +1 more source

A System for Unsteady Pressure Measurements Revisited [PDF]

, 2003
An overview is presented of some recent developments in the field of the design of effective sound absorbers. The first part deals with the application of socalled coupled tubes.
Spiering, R.M.E.J., Tijdeman, H.
core   +1 more source

Impedance measurement using a two-microphone, random-excitation method [PDF]

The feasibility of using a two-microphone, random-excitation technique for the measurement of acoustic impedance was studied. Equations were developed, including the effect of mean flow, which show that acoustic impedance is related to the pressure ratio
Parrott, T. L., Seybert, A. F.
core   +1 more source

Potential Application of Fibers Extracted from Recycled Maple Leaf Waste in Broadband Sound Absorption

Buildings
To address environmental pollution issues and optimize the utilization of waste biomass resources, this study proposes a novel eco-friendly sound-absorbing material based on maple leaf waste and tests its sound absorption performance.
Jie Jin, Yecheng Feng, Haipeng Hao, Yunle Cao, Zhuqing Zhang   +4 more
doaj   +1 more source

Nonlinear acoustic theory for thin porous sheets [PDF]

Nonlinear method for predicting acoustic properties of thin porous ...
Parrott, T. L., Zorumski, W. E.
core   +1 more source

Study and development of acoustic treatment for jet engine tailpipes [PDF]

A study and development program was accomplished to attenuate turbine noise generated in the JT3D turbofan engine. Analytical studies were used to design an acoustic liner for the tailpipe.
Dinwiddie, B. A., III, Hall, O. J., Jr., Linscheid, L. L., Nelson, M. D.   +3 more
core   +1 more source

On-demand prediction of low-frequency average sound absorption coefficient of underwater coating using machine learning

Results in Engineering
This study proposes an underwater coating with sound absorption ability in the middle-to-low frequency range and establishes an acoustic theoretical model combining the equivalent medium theory and the transfer matrix method.
Nansha Gao, Mou Wang, Xiao Liang, Guang Pan   +3 more
doaj   +1 more source

Construction and testing of a modern acoustic impedance tube

, 2001
The acoustic impedance of a material describes its reflective and absorptive properties. Acoustic impedance may be measured in a wide variety of ways. This thesis describes the construction and testing of an acoustic impedance measurement tube which employs modem Fourier Transform techniques.
openaire   +1 more source