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?? Laminar or Turbulent ??

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Old   January 16, 2007, 06:11
Default ?? Laminar or Turbulent ??
  #1
wabik
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Hello,

Could anyone help me? I have to determine in my sytem with complicated geometry if the fluid flow is laminar or turbulent? I need to estimate dimensionless numbers Re, Gr, etc ...

Could anyone please help me with that? Some UDF or other method?

Thank you in advance!!!

Best regards, wabik
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Old   January 16, 2007, 11:33
Default Re: ?? Laminar or Turbulent ??
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Sujith
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These parameters depends on the physics you are modelling... geometry, velocity, materials etc. This can be used as input (not directly) to fluent, not expected to be calculated by fluent.

But still if required you can compute similar parameters through the udf or custom field function. For example cell reynolds number(this is not th e actual reynolds number in physics. ) can be extracted using a CFF.
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Old   January 17, 2007, 03:03
Default Re: ?? Laminar or Turbulent ??
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wabik
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Hi,

These I know but I have to determine the proper model if it is laminar or turbulent or may by somehow transitional.

And if you cold tell me how can I calculate to using two different turbulent models for different materials?

I am modelling Czochralski crystal growth.

Brgds, w.
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Old   January 18, 2007, 11:44
Default Re: ?? Laminar or Turbulent ??
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Sujith
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Czochralski crystal growth--OO--i m not aware of it?

But you must be knowing the following things a range of velocity of the fluid you model. the properties of fluid the geometric features of the domain... these can provide you the reynolds number...

determine laminar or turbulent if turbulent you can start with std k-e. this will provide good enough results. For more accurate results swith to realizable k-e

More complex good models are there, but the are computationally very heavy..

-sujith

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Old   January 19, 2007, 09:11
Default Re: ?? Laminar or Turbulent ??
  #5
wabik
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Hi,

This I know but I wanted to know which model fits the best to reality. So by dimensionless numbers I could do that.

p.
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