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Ralf Schmidt May 11, 2006 08:37

near wall mesh guidelines - y+ to large?

I have a question for the near wall-mesh guidelines from Fluent.

I am modelling heat transfer from a long cylinder in axial flow of Air at Re = 20000.

I am trying to find the best turbulence model to correctly simulate heat transfer. Now, Fluent manual tells me, that for k-e model with std. and non-equilibrium wall functions as well as for the k-w model, the y+ value should be about 30.

In my case, that is resulting in a size of the first cell of about 3 mm (7,5 % of the diameter of the cylinder). And I thing, thats a very big cell.

Also, the resulting Nu and HTC values are not matching experimental data...

Any help is highly appreciated Ralf

mAx May 12, 2006 02:21

Re: near wall mesh guidelines - y+ to large?
Hi, I hae also the same problem. I am working with valves with tiny openings. I never achieved getting first cell with y+ about 30. I am always with y+ about 10. So I would refine your walls (if you hardware enable it :) ) and then switch on Enhanced Wall Treatment.

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