Convergence problem of a thermal stratification tank simulation

hwangpo · April 25, 2013, 01:22

hey guys,

I have been working on this thing, a small tank with temperature stratification, free surface (free slip boundary in CFX), inlet (opening static pressure), and some contractive outlets (mass flow rate).

water density (varying with temperature), temperature (varying with depth), pressure conditions were set through expressions in cfx-pre. And this simulation is steady.

However, it cannot be converged. See attached pics. I have attempted these time steps: 1 s, 20 s, 50 s, 120 s, 200 s (over flow).

what can I do to get this solved?
Do you guys have any suggestions? Thank u so much for your help.

ghorrocks · April 25, 2013, 07:13

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

hwangpo · April 25, 2013, 07:23

sorry for this carelessness. thank u so much.

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April 25, 2013, 07:13		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	FAQ: http://www.cfd-online.com/Wiki/Ansys...gence_criteria

April 25, 2013, 07:23		#3
hwangpo Member Ben B. Huang Join Date: Oct 2012 Posts: 54 Rep Power: 13	sorry for this carelessness. thank u so much.