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-   -   Residual and Imbalance oscillating (http://www.cfd-online.com/Forums/cfx/110485-residual-imbalance-oscillating.html)

Spookz December 12, 2012 06:49

Residual and Imbalance oscillating
 
Hello,

i hope you can help me.

I am currently simulating an autoclave, doing sensitivity analysis on mesh.
Its a simple transient flow simulation without heat transfer.
BCs are:

Reference Pressure: 5 bar
Air at 25C
Inlet: Mass flow
Outlet: Opening (0Pa Opening Pressure)
Initial condition for Fluid: velocity 0 m/s, p=0 bar

I am simulating the first 3 secs of air flow into the autoclave.

1) I have set the residual to 10^-5 and the monitor show, that all equations converge. Anyway residual is still oscillating between 10^-5 and 10^-6.
What does that mean? Has convergence been reached?

2) The imbalance plot does also show oscillation between 10^-2 and 10^-4.
As this is a percentage value, is a value of 10^-2 sufficient for convergence?

3) Do the oscillations have influence on convergence?

Thanks in advance

ghorrocks December 12, 2012 17:19

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


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