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-   -   Interpretation of convergence plots in CFX (http://www.cfd-online.com/Forums/ansys/91863-interpretation-convergence-plots-cfx.html)

Jmac August 24, 2011 20:39

Interpretation of convergence plots in CFX
 
Hi all
I am currently developing a cfd simulation of a shower mixer in CFX, and am having some problems with attaining a decent convergence. I understand that possible faults in the model can be found by analysing features within the convergence plots (eg large oscillations), is there a reference that anyone can point me to that explains these features, and what they say about the model?
Thanks,
James

TrazPT September 2, 2011 13:17

Research Specialist
 
If your steady-state residuals exhibit large oscillations, it's quite likely your physical flow is inherently time-varying. I suggest running the application as a transient solution, saving some .trn files along the way, and then check to see if the convergence behavior improves within each time step. If so, create a transient animation to find the location of the unsteadiness.

Josh September 5, 2011 14:03

Hey James,

Think about it logically. Look at the locations of maximum residuals - is something physically important happening there, or is the mesh quality/resolution poor? You may also find inspiration in an introductory CFD book or this page: http://www.cfd-online.com/Wiki/Ansys_FAQ#Postprocessing


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