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-   -   Mesh Independence and Y + (http://www.cfd-online.com/Forums/fluent/42296-mesh-independence-y.html)

sam September 13, 2006 04:02

Mesh Independence and Y +
 
Dea all

I would to know about the issues related to mesh indepedence and Y+ .

1. What is relationship between Mesh indepdence and y+

2. First we set the y plus or mesh independence .

3. what should be the strategy for meshing while studying mesh independence

4. What should be the strategy for meshing while studying y+

Thanks in advance

Ralf Schmidt September 13, 2006 05:50

Re: Mesh Independence and Y +
 
Hi!

the mesh just passes flow values to the wall function, so u have two different problems!! One is the mesh, if its resolving the gradients well, and the second one is the BL, if the wall function can resolve it well.

The y+ values are set ONLY depending on the wall model you are using. Have a look at section 11.9 of the Fluent manual "Near-Wall Treatments for Wall-Bounded Turbulent Flows".

Independent of the mesh, the y+ values have to fit the values that are given for the wall zone.

For problems with heat transfer or drag coeffizient, it is usefull to do a wall model dependence investigation. Also, for one wall modell (e.g. std.wallfunction - y+ is between 30 and 300) there might be different results for y+ = 30 and 300...

Hope it helps..

Ralf


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