Measuring flow resistivity of porous materials at low frequencies range via acoustic transmitted waves

2006 ◽  
Vol 119 (4) ◽  
pp. 1926-1928 ◽  
Author(s):  
Z. E. A. Fellah ◽  
M. Fellah ◽  
N. Sebaa ◽  
W. Lauriks ◽  
C. Depollier
Keyword(s):  
Porous Materials ◽  
Low Frequencies ◽  
Transmitted Waves ◽  
Flow Resistivity

Measuring permeability of porous materials via acoustic transmitted waves

2005 ◽  
Author(s):  
Z. El Abiddine Fellah ◽  
J.Y. Chapelon ◽  
N. Sebaa ◽  
W. Lauriks ◽  
C. Depollier ◽  
...  
Keyword(s):  
Porous Materials ◽  
Transmitted Waves

scholarly journals Inverse Measurement of the Thickness and Flow Resistivity of Porous Materials via Reflected Low Frequency Waves-Frequency Approach

2021 ◽  
Author(s):  
Mustapha Sadouki
Keyword(s):  
Reflection Coefficient ◽  
Direct Problem ◽  
Fluid Model ◽  
Low Frequency ◽  
Low Frequencies ◽  
Reflected Waves ◽  
Two Samples ◽  
Flow Resistivity ◽  
Theoretical Reflection ◽  
Low Frequency Waves

A direct and inverse method is proposed for measuring the thickness and flow resistivity of a rigid air-saturated porous material using acoustic reflected waves at low frequency. The equivalent fluid model is considered. The interactions between the structure and the fluid are taken by the dynamic tortuosity of the medium introduced by Johnson et al. and the dynamic compressibility of the air introduced by Allard. A simplified expression of the reflection coefficient is obtained at very low frequencies domain (Darcy’s regime). This expression depends only on the thickness and flow resistivity of the porous medium. The simulated reflected signal of the direct problem is obtained by the product of the experimental incident signal and the theoretical reflection coefficient. The inverse problem is solved numerically by minimizing between simulated and experimental reflected signals. The tests are carried out using two samples of polyurethane plastic foam with different thicknesses and resistivity. The inverted values of thickness and flow resistivity are compared with those obtained by conventional methods giving good results.

scholarly journals Impact of entry–exit loss on the measurement of flow resistivity of porous materials

AIP Advances ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 105031
Author(s):  
Swati Sachan ◽  
Sanjeet Kumar ◽  
Shankar Krishnan ◽  
Sripriya Ramamoorthy
Keyword(s):  
Porous Materials ◽  
Flow Resistivity

Measuring permeability of porous materials at low frequency range via acoustic transmitted waves

2007 ◽  
Vol 78 (11) ◽  
pp. 114902 ◽  
Author(s):  
Z. E. A Fellah ◽  
M. Fellah ◽  
F. G. Mitri ◽  
N. Sebaa ◽  
C. Depollier ◽  
...  
Keyword(s):  
Porous Materials ◽  
Low Frequency ◽  
Frequency Range ◽  
Transmitted Waves

Modelling of Rigid-Frame Porous Materials: A Simple Approach

2000 ◽  
Author(s):  
M. J. Brennan ◽  
W. M. To
Keyword(s):  
Porous Material ◽  
Porous Materials ◽  
Characteristic Impedance ◽  
Simple Approach ◽  
Middle Ground ◽  
Acoustic Behaviour ◽  
Rigid Frame ◽  
Flow Resistivity ◽  
Stiffness And Damping ◽  
Optimum Flow

Abstract This paper is concerned with the modelling of rigid-frame porous materials. Currently there are very simple models which describe the acoustic behaviour of such materials, and there are also very complicated models. The aim of this paper is to present a model which occupies the “middle ground”, but is simple enough to be used by practising noise control engineers. Using concepts of acoustic mass, stiffness and damping, non-dimensional expressions for the acoustic wavenumber and the characteristic impedance of a rigid-frame porous material are derived. These expressions are used to give a “rule of thumb” for the optimum flow resistivity for a given thickness of material.

Analysis of Sound Absorption of Date Palm Fibers Based on Flow Resistivity

2013 ◽  
Vol 471 ◽  
pp. 285-290 ◽  
Author(s):  
Elwaleed Awad Khidir ◽  
Mojahed Osman Mohammed Ali ◽  
Mohammed Mustafa Ali ◽  
Mohd Faizal Bin Mat Tahir ◽  
Rozli Zulkifli
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Date Palm ◽  
Single Layer ◽  
Sound Absorption Coefficient ◽  
Low Frequencies ◽  
Palm Fiber ◽  
Date Palm Fibers ◽  
Flow Resistivity ◽  
Fiber Sample

This paper presents a study on the sound absorption properties of a single layer date palm fiber based on the flow resistivity. Experimental measurements were carried out to estimate the flow resistivity value using differential pressure tube. The average diameter of the fibers is 0.462 mm. A date palm fiber sample of 25mm thickness is used in this research. The flow resistivity of the date palm fiber sample was found to be 4.26 kPa.s/m2. The flow resistivity was used to calculate the sound absorption coefficient using Delany and Bazley model. The simulation showed that the values of absorption coefficient are small at low frequencies and rising with increasing frequency. To check the effect of flow resistivity on the sound absorption coefficient Delany and Bazley model was simulated for three different flow resistivity values. The simulation results showed that the sound absorption coefficient increases with the increase of the flow resistivity.

Sign in / Sign up

Export Citation Format

Share Document