Viscosity properties for transport models

ozzythewise · March 20, 2010, 15:27

Hi everyone, I'm new to OpenFOAM and CFD in general. I am trying to understand the different transport models (ie. newtonian, birdcarreau etc). I understand what each one is used for, but I don't know what the viscosity properties represent for each of them. For example, what do nu0, nuInf, m and n for the CrossPowerLaw model? Also, is there somewhere that has a list of what each one represents?

Thanks

ternik · March 23, 2010, 04:38

Quote:

Originally Posted by ozzythewise

Hi everyone, I'm new to OpenFOAM and CFD in general. I am trying to understand the different transport models (ie. newtonian, birdcarreau etc). I understand what each one is used for, but I don't know what the viscosity properties represent for each of them. For example, what do nu0, nuInf, m and n for the CrossPowerLaw model? Also, is there somewhere that has a list of what each one represents?

Thanks

Hi Jeff,

I really suggest to grab hands on a book (actually there are a lot of books) dealing with non-Newtonian fluids and their models; for example

Pierre J. Carreau, Daniel C.R. De Kee and Raj. P. Chhabra: Rheology of Polymeric Systems (Principles and Applications)

is a nice choice! It explains Generalized Newtonian Fluids, Linear Viscoelasticity, Nonlinear Viscoelasticity, ...

Regards,
Primoz

anon_c · March 23, 2010, 04:46

hello

i dont know how about your german

but there is

a book form Giesekus :

Einführung in die phänomenlogische modellierung (springer 1994)

and Böhme

Strömungsmechnaik nicht newtonischer fluide (teubner 2000)

in englisch

Bird, Armstron

polymeric dynamics (willey 1989)

nimasam · October 7, 2010, 11:41

hi jeff osborne
could you find finally what nuInf, nu0, ... means ?
could you find those suggested book?
did you find any reference to explain the crossflow coefficient ?

Locky3827 · October 7, 2010, 21:39

Hi Jeff,
Once you have a handle on the viscosity models from a non-Newtonian book, I suggest that you set up a simple laminar pipe flow in OpenFoam and see the effect of changing the rheology models. There are analytical solutions for pipe flow which can be used for comparison.
Check the shear rate definition in OpenFoam as well as you need the correct shear rate for a correct viscosity calculation, search the forum for the details.
Regards,
Lachlan

March 20, 2010, 15:27	Viscosity properties for transport models	#1
ozzythewise Senior Member jeff osborne Join Date: Mar 2010 Posts: 108 Rep Power: 16	Hi everyone, I'm new to OpenFOAM and CFD in general. I am trying to understand the different transport models (ie. newtonian, birdcarreau etc). I understand what each one is used for, but I don't know what the viscosity properties represent for each of them. For example, what do nu0, nuInf, m and n for the CrossPowerLaw model? Also, is there somewhere that has a list of what each one represents? Thanks

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March 23, 2010, 04:46		#3
anon_c Disabled Join Date: Jul 2009 Posts: 63 Rep Power: 17	hello i dont know how about your german but there is a book form Giesekus : Einführung in die phänomenlogische modellierung (springer 1994) and Böhme Strömungsmechnaik nicht newtonischer fluide (teubner 2000) in englisch Bird, Armstron polymeric dynamics (willey 1989)

October 7, 2010, 11:41		#4
nimasam Senior Member Nima Samkhaniani Join Date: Sep 2009 Location: Tehran, Iran Posts: 1,267 Blog Entries: 1 Rep Power: 25	hi jeff osborne could you find finally what nuInf, nu0, ... means ? could you find those suggested book? did you find any reference to explain the crossflow coefficient ?

October 7, 2010, 21:39		#5
Locky3827 New Member Lachlan Graham Join Date: Dec 2009 Posts: 14 Rep Power: 17	Hi Jeff, Once you have a handle on the viscosity models from a non-Newtonian book, I suggest that you set up a simple laminar pipe flow in OpenFoam and see the effect of changing the rheology models. There are analytical solutions for pipe flow which can be used for comparison. Check the shear rate definition in OpenFoam as well as you need the correct shear rate for a correct viscosity calculation, search the forum for the details. Regards, Lachlan