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Old   April 8, 2005, 17:35
Default Under-relaxation factors
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pUl|
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I know that a converged solution is independent of the value of URF's chosen. However, is it acceptable to change URF's in the middle of a solution and then continue iterating?
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Old   April 9, 2005, 07:49
Default Re: Under-relaxation factors
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ap
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Yes it is acceptable.

You're right when you say that a converged solution does not depend on the value of URF's, but the convergence of a solution is dependent on their values, and also by the combination of them.

Some authors like Peric, for example, suggests some rule of thumb like

a_velocity + a_pressure = 1

where a represents the URF.

Regards, ap
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Old   April 9, 2005, 10:22
Default Re: Under-relaxation factors
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swarup
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regarding URF's,can excessive under-relaxation introduce accuracies in unsteady flows. that is, although solution will be converged but not accurate?

Swarup.
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Old   April 9, 2005, 13:55
Default Re: Under-relaxation factors
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pUl|
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Thanks Swarup, You meant "introduce inaccuracies" right?
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Old   April 9, 2005, 13:56
Default Re: Under-relaxation factors
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Thanks for the information ap. Very well worded indeed!
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