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Old   May 9, 2007, 17:11
Default Meshing refinement
  #1
Zurayk
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Hello,

My question may seem very general,

I have done two models different in meshing density, and the result was that: the one with coarses mesh gives closer results to the experimental data we have. so the one with coarser mesh gives better results, I was wondering if this is explainable generally? or does it depend on the specific case im dealing with? Can a coarser mesh give better results than a finer mesh?

thanx for your time
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Old   May 10, 2007, 04:46
Default Re: Meshing refinement
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Scibor
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The answer to your question is generally NO!!! In particular it depend of what kind of mesh did you use and how do you refine it. If you refine it with an automatic remesh feature it's possible that something strange is happened! If you have reached the same convergence level of the coarse mesh(the same minimum residual) for all variable, try to restart analisys using the AMG solver with the finer mesh, mapping previous solution. The CG solver works fine for coarse mesh but not very well with fine ones. On the user guide U can find something about this argument. Try to use AMG solver with fine mesh, and let me know if something changes, I'm very interested. Bye
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Old   May 14, 2007, 05:57
Default Re: Meshing refinement
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Tom
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I totally agree with Scibor.

maybe one additional comment: In turbulent cases, did you check the y+ value. maybe you get too smnall values with thr refinend mesh. If wall shear-forces become dominant in your application this can also have big influence to your solution.

Tom
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