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k-epsilon without wall functions

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Old   November 4, 2013, 05:37
Default k-epsilon without wall functions
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Samuele Z
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Dear All,

I am trying to solve a very simple problem (a RANS channel foam) and I want to try different turbulence models. The point is that I have a pretty good mesh, hence I want to avoid to use the wall functions for k and epsilon.
Nevertheless, even tough I set different BCs, as soon as I launch the simulation, OpenFOAM automatically writes new files with wallFunctions, both for k and epsilon.

How can I avoid it? Also, has anyone already solved a rans channel flow, with cyclic BC?

Thanks a lot,
Samuele
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Old   November 4, 2013, 12:49
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Onno
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I don't think kEps is the right turbulence model if you don't want to use wall functions. kOmegaSST would probably be preferable.
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Old   November 4, 2013, 12:51
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Samuele Z
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Thanks for answering.

Actually, I was thinking about kEpsilonLowRe (or something like that).

Anyway, the point is: how to avoid wall functions? I mean, if I use the kOmegaSST, are the wall function not used by default?

Thanks a lot,
Samuele
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Old   November 4, 2013, 14:54
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Onno
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Have you read this thread: k-omega SST for wall-resolved TBL, problem with log layer. ?

I think OpenFOAM leaves the BC alone, if you set up a nut-files with type calculated for the walls.
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