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Turbulence and viscosity of non-Newtonian Fluids

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Old   November 14, 2005, 09:00
Default Turbulence and viscosity of non-Newtonian Fluids
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David
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Hello, I use fluent and need to simulate polymer viscosity vs shear rate and the turbulence. I've try with some turbulent models but they want constant viscosity to calculate the turbulence.

Is it possible to copy the non newtonian model in a UDF and then use a turbulent model. I've never try to use UDF until now.

Thank you for advice

David
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Old   November 14, 2005, 10:17
Default Re: Turbulence and viscosity of non-Newtonian Flui
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HVN
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To use turbulence with non-newtonian fluid, you need to activate the turbulence model through the command line not through the GUI.

So to resume, you doesns't need to use UDF for your problem.
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Old   November 16, 2005, 10:26
Default Re: Turbulence and viscosity of non-Newtonian Flui
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David
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I wrote

define/models/viscous/turbulence-expert/turb-non-newtonian?

but the command is not valide. I received this message "invalid command".

Thanks
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Old   November 16, 2005, 10:52
Default Re: Turbulence and viscosity of non-Newtonian Flui
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Wael
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What version of Fluent do you have? in 6.0.12 the command is not available.
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Old   November 17, 2005, 05:08
Default Re: Turbulence and viscosity of non-Newtonian Flui
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David
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The version is Fluent 6.2.16.

Is it possible to check if I have all the libraries to use the turbulence with the viscosity of non newtonian fluids.
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Old   November 17, 2005, 05:39
Default Re: Turbulence and viscosity of non-Newtonian Flui
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Wael
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Hi David, First select the standard k-e model, then use TUI and write define\model\viscous\turbulent expert\ Then you can select

turb-non-newtonian? Enable turbulence for Non-Newtonian fluids.

non-newtonian-modification? Enable Non-Newtonian modification for Lam-Bremhorst model.

Hope that can help - Wael
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Old   November 17, 2005, 12:23
Default Re: Turbulence and viscosity of non-Newtonian Flui
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David
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Thank you a lot.

I use it with non newtonian power law.

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Old   November 29, 2005, 08:09
Default Re: Turbulence and viscosity of non-Newtonian Flui
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Zahra
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I wanted to define viscosity by this function:

v=v0*exp(b(T-T0))*g^n where : v=viscosity b=constant T=temperatur g=shear rate

thanks for you kind help
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