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Momentum source coefficient and convergence

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Old   November 19, 2010, 05:26
Default Momentum source coefficient and convergence
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meh
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Matt
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Hi

I'm applying momentum source coefficients over a sub domain which are dependent on velocity. Without a momentum source coefficient I was not getting convergence. I've found that a momentum source coefficient of -100000 allows the model to converge, and the results are accurate. I did this based on what the manual says:

General Momentum Source
Momentum sources can be specified directly in terms of a momentum value per unit volume in a specified direction. To obtain good convergence when the source is a function of velocity, the source should be linearized by including a Momentum Source Coefficient.

However I don't understand why this works - can anyone explain? Or suggest a reference?

Why does the momentum source coefficient improve convergence?

Thanks, Matt
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Old   November 19, 2010, 13:44
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This required by the specific solver technology of CFX. I guess it is describbed in the manual how to linearize. If not you have to ask the service.
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Old   November 19, 2010, 17:57
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This is a complex question. I will have to refer you to CFD text books like "Introduction to Computational FLuid Dynamics" by Versteeg and Malalasekera.
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