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mateus February 26, 2004 09:14

non-newtonian fluids

I need to model a problem involoving non-newtonian fluid, but I can't find where do I have to put the viscosity data in fluent. The manual says that different models (non-newtonian Power law, carreau model, cross model and herschel-bulkley model) for non-newtonian fluids can be found in Materials-viscosity drop down list, but they are not there.

Help is greatelly appriciated.


ap February 26, 2004 13:51

Re: non-newtonian fluids
Just start FLUENT, go to the Materials panel. If you click on the drop down list for viscosity expression, you can see the models you're looking for.

Hi :)


mateus February 27, 2004 04:14

Re: non-newtonian fluids
Hi Ap!

Thanks for the fast responce. Strange thing. If you first define the materials (non-newtonian) and then read msh file it works. If you read a case file and then try to change the material properties to non-newtonian, the models are not there...

Thanks again!


ap February 27, 2004 08:10

Re: non-newtonian fluids
FLUENT misteries :)

Good work


ramone February 27, 2004 10:06

Re: non-newtonian fluids
non-newtonian models are only avalaibles in laminar. If in your case file a turbulent model is selected, non-newtonian models will not be avalaible.

HVN February 27, 2004 10:40

Re: non-newtonian fluids
If you want to use non-newtonian fluid with turbulence, you need to activate this option through command line in the fluent interface.

mateus February 28, 2004 07:37

Re: non-newtonian fluids

You're right! Figure have to write... define/models/viscous/turbulence-expert/turb-non-newtonian? and then select yes. I don't get it why this kind of stuff isn't mentioned in manual.

Does enyone have some expirience with non-newtonian fluids (nnf). I have a free surface problem with nnf. I have to simulate a mixing prosess (only mixer in one fluid). I have a lot of expirience with VoF bun non with nnf. The simulation works fine if i use water, bud deverges with nnf. What turbulence model should be used here. If I work laminar it converges.

thanks for your help


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