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-   -   Momentum source coefficient and convergence (https://www.cfd-online.com/Forums/cfx/82187-momentum-source-coefficient-convergence.html)

meh November 19, 2010 05:26

Momentum source coefficient and convergence
 
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

joey2007 November 19, 2010 13:44

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.

ghorrocks November 19, 2010 17:57

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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