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Refinement criteria

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Old   August 30, 2003, 05:49
Default Refinement criteria
  #1
Julie Polyakh
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How do I choose the refinement criteria and the value of per cent of cells being refined?
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Old   August 30, 2003, 08:32
Default Re: Refinement criteria
  #2
allan
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experience.

Are you refining because you have a converged solution and you want better resolution, or it is not converged?

allan
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Old   August 30, 2003, 09:11
Default Re: Refinement criteria
  #3
Julie Polyakh
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I need to perform a grid-independence check.
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Old   September 1, 2003, 14:49
Default Re: Refinement criteria
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allan
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well!

double the number of cells in each direction then

allan
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Old   September 1, 2003, 15:45
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Joern Beilke
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... but even a converged and grid independend solution might be completely wrong.

You should look for the correct solution
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Old   September 2, 2003, 04:57
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Thomas
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search for Richardson extrapolation. It is quite old stuff (around 1920, I guess) but it is a mathematical procedure to obtain a grid independent solution.

you have to start with a coarse mesh and then refine it twice by facor 2 in each dimension (2x2x2 for 3D case). then you to put the results (pressure drop, temperature increase/decrease or whatever into an equation and you will get the so called grid-independent solution. but keep in mind: this does not mean, you get the 'right' solution!

thomas
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Old   September 2, 2003, 10:28
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Ulf
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This is a respond to Joern and Thomas. If you have a grid-independend solution, you will THE solution for the problem that you have specified.
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Old   September 2, 2003, 15:07
Default Re: Refinement criteria
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Joern Beilke
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You probably have the solution for the mathematical problem you have specified but not for the psysical problem which you want to solve.

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Old   September 2, 2003, 23:41
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Ulf
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Yes, I agree with you. But this was not the question in the first place...
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Old   January 6, 2004, 09:51
Default Re: Refinement criteria
  #10
khelil ali
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BONJOUR il faut rafiner le maillage au niveau des parois et dans les zones de grandes perturbation "zones de recirculation et à l'entrée.
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