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-   -   2 domains - 2 physical timesteps? How to? (https://www.cfd-online.com/Forums/cfx/63144-2-domains-2-physical-timesteps-how.html)

flattie March 30, 2009 12:36

2 domains - 2 physical timesteps? How to?
 
I have 2 fluid domains with a solid between them. How can I set two different physical timesteps, without resorting to autotimestepping, which I don't want to use? The size of my domains is vastly different and the timescale needed to get the small domain to converge leads to very slow convergence on the large domain.

Thanks!

Craig Hildreth

rikio March 30, 2009 20:42

Local Timescale Factor can be used to set different timescales for different domains automatically. Please refer to section of "Steady State Time Scale Control" in HELP.
Wish it helps.

flattie March 31, 2009 11:31

Thanks, but doesn't Localtimescale factor have a different timestep on an element basis rather than a domain one? I want to set the timestep for the domain as a whole.

stumpy April 4, 2009 20:44

You can do this, but it's CCL only. Essentially copy the entire SOLVER CONTROL section and paste it under the DOMAIN section. Delete all the parameter except the timescale control parameters.
Mike

rikio April 5, 2009 04:01

Stumpy,

Does it work? I will have a try on this to check this "new" feature...hehe

stumpy April 5, 2009 19:27

Yeh, it works, I've used it before. You can do phase-specific timescales too in a similar way by pasting into the FLUID object of a domain. If you know how to read the RULES file (<install dir>/etc/RULES) you can see that SOLVER CONTROL is a valid child of a DOMAIN object.


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