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-   -   __CrossPowerLawCoeffs & BirdCarreauCoeffs__ (http://www.cfd-online.com/Forums/openfoam/84345-__crosspowerlawcoeffs-birdcarreaucoeffs__.html)

maysmech January 26, 2011 16:30

__CrossPowerLawCoeffs & BirdCarreauCoeffs__
 
Dear FOAMers,
What is CrossPowerLawCoeffs and BirdCarreauCoeffs?
Does it should be changed if nu be changed from 1e-5 to 1e-6?
Thanks in advance

Quote:

transportModel Newtonian;

nu nu [0 2 -1 0 0 0 0] 1e-05;

CrossPowerLawCoeffs
{
nu0 nu0 [0 2 -1 0 0 0 0] 1e-06;
nuInf nuInf [0 2 -1 0 0 0 0] 1e-06;
m m [0 0 1 0 0 0 0] 1;
n n [0 0 0 0 0 0 0] 1;
}

BirdCarreauCoeffs
{
nu0 nu0 [0 2 -1 0 0 0 0] 1e-06;
nuInf nuInf [0 2 -1 0 0 0 0] 1e-06;
k k [0 0 1 0 0 0 0] 0;
n n [0 0 0 0 0 0 0] 1;
}

MartinB January 26, 2011 16:41

Hi,

CrossPowerLawCoeffs and BirdCarreauCoeffs will not be read since the transportModel is set to "Newtonian". A change of nu to 1e-6 therefor has influence to your simulation, but no influence to the other transport models.

Change the transportModel to "CrossPowerLaw" to use Cross Power Law or change it to "BirdCarreau" to use Bird Carreau Model.

More information about the Carreau model can be found here:
http://en.wikipedia.org/wiki/Carreau_fluid

If you are looking for variants of shear thinning fluids model feel free to ask...

Martin

maysmech January 26, 2011 16:55

Quote:

Originally Posted by MartinB (Post 292333)
Hi,

CrossPowerLawCoeffs and BirdCarreauCoeffs will not be read since the transportModel is set to "Newtonian". A change of nu to 1e-6 therefor has influence to your simulation, but no influence to the other transport models.

Change the transportModel to "CrossPowerLaw" to use Cross Power Law or change it to "BirdCarreau" to use Bird Carreau Model.

More information about the Carreau model can be found here:
http://en.wikipedia.org/wiki/Carreau_fluid

If you are looking for variants of shear thinning fluids model feel free to ask...

Martin

Thank you very much.:)


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