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taedeneo September 10, 2009 08:40

relaxation factor for coupling in FSI simulation
Hi All,
I am currently working on a project in FSI which I need to use non-constant value for under relaxation factors of the coupling. For Example, I want to use relaxation factors of 0.1 for the first few stagger iterations and then change it to 1. I have tried putting in an expression to tell the solver to do what I want above but CFX returns an error saying that only numeric value can be used. Is there anyway to do this? Also, I thought if it cannot be inserted in the CFX-pre(CCL), then maybe it can be done by going into the MMS and overwrite the value at the beginning of each stagger iteration. However, I am trying browsing the data location of the relaxation factor of the coupling but I couldn't find anything since I don't know its solver name and not even sure that the value is stored in MMS of CFX. Any idea would be appreciated!:eek:


ghorrocks September 10, 2009 18:22

The easiest way sounds like stopping the simulation, resetting the URF and restarting. This can all be scripted so it still can run efficiently.

taedeneo September 11, 2009 03:09

Hi Ghorrock,
Thanks for your reply. Could you give me some guideline of how to do the scripting?

ghorrocks September 11, 2009 07:29

The documentation discusses starting the CFX solver from the command line. This gives you all the solver run-time options. Then probably use a CCL file to change the things you wish. Look for the commands "cfx5cmds" and "cfx5solve".

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