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Old   July 24, 2003, 16:48
Default a problem with UDF
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Baz
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Hi, I have a problem with interpreted UDF . I wrote a simple initialization function for density gradient and after I initialize the solution, I can see contours of variable density. But, even after one iteration the density changes into constant. Why? Thank you for help.
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Old   July 24, 2003, 23:56
Default Re: a problem with UDF
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ccc
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hi, I have similar problems. if anyone know, think in advance.
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Old   July 25, 2003, 06:12
Default Re: a problem with UDF
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Ale
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Hi,

perhaps I didn't get the point, but that's what I think: If you initialize a variable, however you do that, you give an initial approximation of the solution. If your model doesn't change the density during the calculation, and you've set a constant value for density in the Materials panel, at the second iteration you'll get that value in all the domain.

You should probably write a DEFINE_PROPERTY macro in your UDF, defining the law of change of your density during the simulation.

Good luck,

Ale
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Old   July 25, 2003, 10:53
Default Re: a problem with UDF
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ap
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I agree with Ale.

If you keep constant the density in Material properties, FLUENT will use your initialization value just to compute the first iteration.

Hi

ap
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Old   July 26, 2003, 19:39
Default Re: a problem with UDF
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Lola
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I thought after 'first iteration', the solution is NOT 'converged'. Why would I bother checking any solution in some intermediate iterations??
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Old   July 27, 2003, 20:22
Default Re: a problem with UDF
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ap
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I'm not telling the solution is converged after the first iteration.

I just say that if you initialize a density value, but you keep constant density in the material properties, FLUENT will use the value specified there (Material properties) to do all computation except for the first iteration.

Hi

ap
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