[bengy]

hello,
how to improve prism layers in the corner? I mean what I should do to create prism layers which are not convergent in the corner. I have very good mesh so informations and tips from help doesn't work (it works only for poor quality mesh).

[Maddin]

Show a picture plz.

[bengy]

that's it.......

[Maddin]

You can't do anything. Support also didn't know a work around...
I had the same problem...

[bengy]

yeah that's true - support also didn't know. it's very strange so I decided to concentrate mesh closely to boundary (between prism layers and core mesh)

[djack]

Hi everyone,
I'm meshing a container using star ccm trimmer and prism layer model.
I'd like to know if it was possible to crossover two different prism layer in a corner to increase mesh definition in that region.
If possible that may be a solution for bengy
thanks,
Djack

[siara817]

I think if you reduce the prism layer stretching in the mesh/reference values/prism layer stretching, you can have finer meshing.

[rwryne]

Originally Posted by bengy

that's it.......

Are you using 7.02 or 7.04? If so, try using the "advancing layer mesher". It is a new meshing model that will handle those corners better. read about it in the help file, they have screenshots of a Poly+Prism vs Advancing Layer for very similar geometry.

[rwryne]

Here is a quick example I made comparing the two....I did exagerate the prism layer thickness to highlight the differences.

[djack]

I'm using 6.04...
Anyway thanks for the answer.
djack

[rwryne]

Originally Posted by djack

I'm using 6.04...
Anyway thanks for the answer.
djack

We don't get to say this often, but try coarsening your grid. It seems to happen as a function of OverallHeight / Surface Cell Size. Just keep increasing your surface cell size until the problem goes away, and then see if this is an acceptable size....if not, try decreasing your overall prism layer height.

[eRzBeNgEl]

the new mesh type advanced layer meshing is the solution for this problem

[djack]

I never heard about that mesh type. Is it available in Star ccm 6.04.
Djack

[rwryne]

Originally Posted by djack

I never heard about that mesh type. Is it available in Star ccm 6.04.
Djack

It is the same mesh type I was referring to in my posts from 3 weeks ago, and it was introduced in 7.02 and improved in 7.04

[djack]

I'm now using starccm 7.06 and as you said it works !
Thanks you all,
Djack

[abdul099]

The main question is: Why do you think, this mesh would be bad in the corner?

[djack]

I see two arguments :
- Actually the velocity magnitude in the corner is smaller than far from the corner, then the solution may be to increase the prism layer height in the corner (law of the wall). That's definetly not the case for the old prism layer meshing system where the prism height was decreasing.
- I guess it's better to keep the same prism layer structure when geting closer to the corner.

[renee]

I know this topic is a bit old but I am currently facing the same problem.
My Prism Layer Setup results in the same way bengy posted with his picture above. I did a short mesh study by variing different values. So far it looks like my prism layer thickness is to high.

Can somebody please explain me why the weird corner prism layer structure could cause a lower mesh quality? Sure, the y+ value should be constant but the y+ is only dependent on the first layer hight which not too much affected as you could see in the picture bengy posted.

Thanks a lot in advance.

Rene

[ibrababz]

I have a similar problem at the trailing edge of an airfoil.

The prism layer (which needs to be this thick) horribly converges at the tail of the airfoil.

I have even disabled the prism layer at the trailing edge and only applied it to the main body, but it still does not change the strange convergence.

A picture is attached.

Any potential solutions?

Thanks,
Ibrahim

[Eike]

Maybe you should consider a small radius at the edge.

There is a workshop "Near Core Layer Aspect Ratio" (STAR-CCM+ 11.02) which could help. The topic is to improve the mesh/prism-mesh of a turbine blade.