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-   -   Residuals Plot (https://www.cfd-online.com/Forums/fluent/95309-residuals-plot.html)

kamalipour December 13, 2011 08:30

Residuals Plot
 
Hello everyone.
as I am new to this good site, I have a lot of questions about Fluent and GAMBIT. Hope you help me.
I start my first question about Residuals Plot.
What mean Residuals Plot?
How it should be?
Thank you dears.

kvloover December 14, 2011 16:45

In theory the residual is the difference between your current (iterated) value and the exact solution.
Now since fluent doesn't know the exact solution, afaik the residual is the difference between the values of two iterations. (be it maximum, weighted or...)

A small residual in principal gives the more accurate solution. However the mesh can converge to a wrong value if it's not made properly. For this a seperate mesh/grid independance study is needed.

A decent value for the momentum residual would be E-05.
(And it should overall be going down -even slowly-, else it's unstable)

kamalipour December 15, 2011 04:44

Thank you dear Kevin for your reply.
How to understand that converge is wrong? Is this possible?
and can you suggest me a refrance for studding about mesh/grid?


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