I think you can use COMSOL multiphysics. Don't know if the resistivity is directly computed, but you should be able to easily implement constitutive equation for it in the model builder.

Hi

I have never used it myself, but I believe that Foam-X uses a Biot theory FE models to fit simulation data to test data för absorber materials. You get a bunch of parameters from this fit, which is good as the structure factor may be affected from structural boundary conditions when you insert acoustic metarials in a test tube. http://www.mecanum.com/software-acoustic-characterization-FoamX.html

For some data on absorbers + some theory, you may want to take a look here.

https://books.google.se/books?id=At95BgAAQBAJ&pg=PA272&dq=porous+material+flow+resistivity+table&hl=sv&sa=X&ei=lOL0VPrZOuThywOAi4LIAg&ved=0CFMQ6AEwBQ#v=onepage&q=porous%20material%20flow%20resistivity%20table&f=false

Sincerely

Claes

The static air-flow resistivity depends on your material micro-structure. It cannot be estimated without experimental measurements [1] unless you're doing virtual prototyping (also known as micro-macro approaches [2]).

However, you may find information in some publications. For example, if your material is a glass-wool, have a look at the work by Delany & Bazley [3] (OK it dates back in 1970 and the manufacturing processes have changed a little since then).

To compute the sound absorption from the value of the static-air-flow resistivity, you can try the Matlab/GNU Octave code at the bottom of this page on APMR:

http://apmr.matelys.com/PropagationModels/MotionlessSkeleton/DelanyBazleyModel.html

You can also check for gTMMa (a free but basic C implementation of the Transfer Matrix Method for Acoustics: http://gtmma.sourceforge.net , it implements the Delany-Bazley model as well).

[1]: http://apmr.matelys.com/Parameters/Characterization/Acoustics/StaticAirFlowResistivityMeasurement.html

[2]: http://apmr.matelys.com/PropagationModels/MicroStructureToMacroProperties.html

[3]: Delany M. E. and Bazley E. N., Acoustical properties of fibrous absorbent materials, Applied Acoustics 3, 1970, pp. 105-116

http://dx.doi.org/10.1016/0003-682X(70)90031-9

Hi Mathan,

If you have a material micro-structure model, you can use Comsol that allows you to solve the Navier-Stokes equation, with or without the local incompressibility condition, and the heat equation. Please note that, in order to obtain the air-flow resistivity, a very low frequency is required. This assumption allows you to simplify the resolution of the mesh.

Hi Mathan

There are three cases:

+you can calculate from the specimen:(measure directly )

http://www.mecanum.com/static-airflow-resistivity-meter.html

use equipment resistivity-meter of mecanum.ca

+You can model the structure of materials by Comsol (ordinary micro-structure) and based on the basic equation for calculating. (Laminar Flow Element)

+ Once you've got the experimental results. Exactly for use Foam-X

http://www.mecanum.com/software-acoustic-characterization-FoamX.html

Sincerely

VU

yes it could be calculated , please find the below article

Article Air Flow Resistance and Sound Absorption Behavior of Open-ce...