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-   -   convergence and conservation target of h-energy euqation (https://www.cfd-online.com/Forums/cfx/87399-convergence-conservation-target-h-energy-euqation.html)

gitsnedbutzi April 19, 2011 09:50

convergence and conservation target of h-energy euqation
 
Hi,

I have a simulation consisting of two domains, a fluid and solid one.
However, I am struggling to achieve convergence to a residual of 1e-5 during the steady state simulation, which should be the starting point for a transient simulation.

During the transient simulation, I achieve convergence but not the conservation target of 1%. The imbalance is about 1,5%.

So far I have been struggling to achieve both targets. Any ideas on how to improve convergence and achieve the conservation target would be greatly appreciated!!

Thanks

ghorrocks April 19, 2011 21:24

CHT simulations often like a generous solid time scale factor. This advances time in the solid region faster than the fluid region as the time scales in the solid region are usually far slower than the fluid time scales.

gitsnedbutzi April 20, 2011 13:41

thanks, i wouldnt be worried if the convergence is slower. however the residual stagnates and doesnt converge at all. aren't there options for the solver / preconditioner that help. the only thing i have seen is the time scale factor, but it doesnt help.

ghorrocks April 20, 2011 18:58

http://www.cfd-online.com/Wiki/Ansys...gence_criteria


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