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Problem with Transport of diluted species concentration calculation

Posted Sep 1, 2015, 10:41 p.m. EDT Fluid & Heat, Computational Fluid Dynamics (CFD) Version 4.4 0 Replies

Houari Cobas
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Hello, I am trying to model a system which is formed by four inputs channels, for ech one of them water is flowing. Besides it is another input, a central one, for which flows an organic material. I´m using the transport of diluted species and a laminar flow physics.
For a certain mesh size, the problem seems to match the theoretical output concentration with relative errors lower than 4%. In order to increase solution accuracy i had reduced evem more the mesh size. For the new mesh size i had almost 1,5 millions DOFs.
The new model was solved out in 17 hours. Surprisingly, for the new results, the output concentration was much lower than the previous ones and hince the error relative to the theoretical values.
i was thinking that decreasing mesh size would improve the simulation accuracy, not make it worst.
Could someone please wive me and idea about what should be happening and what should i do to fix it?

thank you very much
0 Replies Last Post Sep 1, 2015, 10:41 p.m. EDT
COMSOL Moderator

Hello Houari Cobas

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