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Convergence issues in a non-isothermal flow problem
Posted 09.07.2012, 10:02 GMT-4 Fluid & Heat, Heat Transfer & Phase Change, Computational Fluid Dynamics (CFD), Studies & Solvers Version 4.2a 1 Reply
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I have encountered a problem while trying to solve a non-isothermal flow problem. The model features a repetitive unit cell of a dynamic insulating wall element. The intention is to simulate its performance. There is no problem when the flow rate is set to a relatively high level (for instance 1.0 m/s), but so far I cannot get it to converge to an acceptable error level at the desired flow rate (order of 0.01 m/s).
I am quite the beginner using comsol, so it may just be a very simple issue. Is there anyone who can help me?
Thanks in advance.
Edit: I did just find out that when the volume force working on the free flowing air is neglected, so the volume force only works on the closed pocket, it does converge without any problems. However, this assumption cannot always be justified...
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Add "Pressure Point Constraint" inside closed pocket (lower point on symmetry axis) and use fine mesh. After this convergence is working.
Best regards
Tero