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Old   November 9, 2004, 08:42
Default CONVERGENCE
  #1
Hellen
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I have a big problem with the code I am working on. The problem is CONVERGENCE, it does not converge, but deos not dirverge either. The time history of the error is fluctuating, no matter how many steps, 1000 or 200,000. If anybody can help me out what the problem might be would be a great help for me. Thanks.
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Old   November 9, 2004, 09:36
Default Re: CONVERGENCE
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zqnwpu
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So many things can cause this! maybe grid ,boundary conditions etc.

Can u describe your quesion in detail?
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Old   November 9, 2004, 13:19
Default Re: CONVERGENCE
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Jarmo Monttinen
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What is the geometry, which equations are you solving, what flow conditions. Sounds like you have something time-dependent going on.

-- Jarmo
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Old   November 9, 2004, 21:53
Default Re: CONVERGENCE
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zxaar
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you haven't mentioned around what value it is fluctuating ... after some value generally it starts fluctuating or becomes constant .. ..usually around 1.0E-07 , that is it is not necessary that it will always keep on falling (generally not)
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Old   November 10, 2004, 04:42
Default Re: CONVERGENCE
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Mikael Ersson
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I think that depends on how you define the convergence criterion.
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Old   November 13, 2004, 03:36
Default Re: CONVERGENCE
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avis
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Maybe you can use a previous convergenced calculation as starting point, as well changing the discretization, Courant o reducing the relaxation factors maybe you will found a solution. Itīs posible that your starting values are not appropiated, try to change this as well.
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