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Convergence Problem using 2. order implicited time discretization

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Old   January 23, 2014, 09:37
Question Convergence Problem using 2. order implicited time discretization
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Tom Marquardt
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Hey guys,

I'm simulating melting behaviour in a 2D geometry, dominated by natural convection.

I already did a grid dependency study and calculated a time step, which should be small enough.

So far my residuals fulfilled the criteria easily (10-6/10-6/10-6 and 10-10 for energy) with an average of 6 Iterations.

I changed from First order to second order implicid (nothing else!) and now the residuals for continuity stop decreasing at around 10-3 and I have no idea why.

Any suggestions?

Thanks in advance

Tom
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Old   January 23, 2014, 09:41
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Tom Marquardt
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Screenshot of my residuals
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Old   January 24, 2014, 08:18
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Any ideas?
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