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crosspowerlaw nu0 and nuinf, which is bigger?

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Old   January 6, 2013, 05:17
Default crosspowerlaw nu0 and nuinf, which is bigger?
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Dongyue Li
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return (nu0_ - nuInf_)/(scalar(1) + pow(m_*strainRate(), n_)) + nuInf_;

According to this, nu0 is the kinematic viscosity when the stress rate tends to zero. and nuinf is the one that the stress rate tends to infinate.

Quote:
transportModel CrossPowerLaw;

CrossPowerLawCoeffs
{
nu0 nu0 [ 0 2 -1 0 0 0 0 ] 0.01;
nuInf nuInf [ 0 2 -1 0 0 0 0 ] 10;
m m [ 0 0 1 0 0 0 0 ] 0.4;
n n [ 0 0 0 0 0 0 0 ] 3;
}
Should it be nu0 bigger than nuinf?

but in the tutorial case is opposite.

Last edited by sharonyue; January 6, 2013 at 05:53.
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Old   January 6, 2013, 05:59
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Maybe I figure it out, in this case n>3 which indicate its Shear thickening. I will validate it soon.
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Old   January 7, 2013, 00:59
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nu_0 is lesser in this case then the nu_inf, as n >1.
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Old   January 17, 2013, 09:35
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Quote:
Originally Posted by Tushar_Mtechcfd View Post
nu_0 is lesser in this case then the nu_inf, as n >1.
Hi Tushar
Code:
m m [ 0 0 1 0 0 0 0 ] 0.4;
Does this m mean consistency index? but consistency index's dimension is not this. I am confused.
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Old   March 7, 2013, 03:49
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Quote:
Originally Posted by sharonyue View Post
Hi Tushar
Code:
m m [ 0 0 1 0 0 0 0 ] 0.4;
Does this m mean consistency index? but consistency index's dimension is not this. I am confused.
Does anybody know whats the meaning of m?
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Old   April 1, 2013, 01:29
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Quote:
Originally Posted by sharonyue View Post
Does anybody know whats the meaning of m?

m actually is a natural time.
I think you are trying to co-relate with powerlaw but this isn't correct. The mentioned model is CrossPowerLaw and it is different from PowerLaw. Try looking some more literature on it.

Best of luck.
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Old   April 1, 2013, 03:44
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Quote:
Originally Posted by Tushar@cfd View Post
m actually is a natural time.
I think you are trying to co-relate with powerlaw but this isn't correct. The mentioned model is CrossPowerLaw and it is different from PowerLaw. Try looking some more literature on it.

Best of luck.
Woo,Tushar,

That really helps me alot.I check it out and find its natural time from one paper.

But in another paper it said this:

Why is it so different?

Thanks a lot!

Regards,
Attached Images
File Type: jpg 1.jpg (73.8 KB, 27 views)
File Type: jpg 2.jpg (65.5 KB, 30 views)
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Old   April 1, 2013, 08:13
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Quote:
Originally Posted by sharonyue View Post
Woo,Tushar,

That really helps me alot.I check it out and find its natural time from one paper.

But in another paper it said this:

Why is it so different?

Thanks a lot!

Regards,
Well sharonyue, nice question.
I think, this may be because we are trying to match a range as mentioned in the 2.jpg
It's just a guess, I am also not sure.

Do let us know if you happen to find the answer.
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