[ruzfactor]

Most of the y+ values within the wall for my mesh is between 15~20. Which is the best adaptation in FLUENT (gradient, y+...) to get the y+ value more than 30?? Once I used gradient adaptation and the y+ value then falls in the viscous laminar region (y+<5).

[BH2010]

To coarsen the mesh:
Adapt -> y+
Then set the Min Allowed to, say, 50
max allowed to what-you-want
click mark and you see the numbers of cells to be adaptedu can see these cells with "manage" - "display"

then click on "adapt"

Greetings,
Boris

[ruzfactor]

@BH 2010:

I have tried that but it says 0 cells marked for refinement or coarsen.
(I have set Min: 30 Max: 50). May be that's because none of my cells have values of 30. I get Min 0 and Max 26.48063 when click on compute. How do I coarsen then?

[BH2010]

try setting min=27, max=100, then all cells should be marked as "coarsen". Then adapt.

[ruzfactor]

I have done that. But after adapting it says, 0 change. May be FLUENT can't coarsen mesh.

[Newb]

Only meshes that have previously been refined by Fluent itself can be coarsened. That is, if you start with a fresh mesh, for example one built in Icem, Fluent will not coarsen it, even if the y+ adaptation requires it.

[smhasheminasab]

so how we can adapt(coarsen) a fresh mesh which has y+ less than 30?