[Far]

Originally Posted by diamondx

i often get the same prism generation, did you try generating ONE big layer of prism instead, and dividing it ?

Why this not happen in T-Grid?

[diamondx]

Why this not happen in T-Grid?

Can't really tell... try to generate one layer on prism, then divide it in edit mesh tab, go to the prism section and you will find divide prism, see if you can get a better result.
Also in the screenshot that you showed us, the prism were generated after the surface meshingand without the volume mesh. if you generete the volume mesh then the prism i'm sure you will get a better looking prism layers. why ? i don't know

[Far]

I did prism generation after volume mesh. Tetra are not turned on...

[diamondx]

ah ok... yeah doesn't look good there. how about the other option i suggested

[Far]

Originally Posted by diamondx

ah ok... yeah doesn't look good there. how about the other option i suggested

I will try it. But T-grid is awesome

[diamondx]

i generated my first volume mesh yesterday with the tutorials. it is really fast !!!

[Far]

Do you need input mesh files ?

[diamondx]

for this formula one ???

[Far]

Originally Posted by diamondx

for this formula one ???

This can be shared if needed. But I am talking about T-grid input files!

[diamondx]

i have them... thanks

[diamondx]

yesterday i got my hand on pointwise. it took me more than 30 min to know how to rotate the geometry as i wanted

[Far]

You are good enough. Even it took me weeks to know how to make the simple mesh in Gambit

[cfd seeker]

Far and Diamondx....generating one prism layer and then splitting it to further parts is not a good idea as it produces bad quality prisms(again told to me by Simon). Instead generate atleast three layers and then split them but this splitting operation is not designed to give you good quality rather it is there to save time as splitting operation takes less time than generating the same no. of layers in the initial mesh and also to get your desired wall y+.

Anyhow the procedure is....Edit Mesh>Split Prisms....here there are two options to split prisms i.e Fixed initail height and Unifrom ratio, first will option will ensure the fixed height of 1st layer and later will ensure the unifrom distribution of prisms. After this you can go to Move Nodes>Redistribute Prisms...here again there are two options i.e Fixed Initial height and Uniform ratio. This option redistribute the splitted layers to give you a nice growing and properly distributed mesh in the B.L

[BrolY]

All those tricks are explained in the ICEM tips and tricks document made by Simon, aren't they ?
There are some posts about the right procedure to create prism on this forum (again based on Simon's tricks and tips ). The way I have always used is this one :

1) surface mesh (patch dependent if your geometry is good enough, otherwise, patch independent by volume mesh then delete volume mesh). Don't forget the build topology
2) smooth until nothing the quality is good : very important to have a good volume mesh after and good prisms
3) volume mesh (delaunay AF+TGLIB)
4) smooth until nothing the quality is good
SAVE your project.

Then you go for prism :
1) try to create as many layers as you want and see if it works.
if not, try the option explains and the Simon's tips and tricks document
2) if it doesn't work, try what CFD Seeker said. you can try one prism layer splitted in as many you want, or 3 prisms layers then split.
It depends on how many prism layers you want. If you want only 5 prism layers, just create 1 and split it in 5 after. If you want 20 prism layers, then create 5 and split it after would be a better way.

[PSYMN]

Sorry I have been so busy lately... Far emailed me and asked me to stick my head in, but this thread has moved a long way since then. I noticed 2 questions.

1) Yes, if you have some surfaces meshed with patch conforming before you run Octree, you can keep the patch conforming mesh... It is an option when you compute mesh. Change the pull down to "geometry and mesh" and select the parts where you want to keep the mesh.

2) If you assign prism to a surface, like that tire, it will stair step off as it approaches the edge. It does this to prevent a solution where you have all the prisms ending along one plane, particularly very thin prisms with pyramids sticking out into the tetra volume. The best solution is to include the side surfaces in your prism selection. Then prism will be full on the surface you want and will taper off on the adjacent surface.

[cfd seeker]

2) If you assign prism to a surface, like that tire, it will stair step off as it approaches the edge. It does this to prevent a solution where you have all the prisms ending along one plane, particularly very thin prisms with pyramids sticking out into the tetra volume. The best solution is to include the side surfaces in your prism selection. Then prism will be full on the surface you want and will taper off on the adjacent surface.

I didn't get this point...can some one among you guys Far, diamondx, broly explain it may be with some example and with some pics....

[diamondx]

yeah i will, i have an example in my lab, let me get back to you later on this

[diamondx]

@ cfd seeker, i came to lab i realized i flushed away the mesh i had sorry about that.
the stair step is a normal and it happen because the prisms have to end somewhere. if the surface with the prism is really important to you, you can add prism to surface next to it too so you extend where the stair step appear...

[diamondx]

We've just made this thread as the most discussed one in the ansys meshing section. thanks to the love story between scipy and far ... congratulation.

[Far]

Originally Posted by PSYMN

Ys, if you have some surfaces meshed with patch conforming before you run Octree, you can keep the patch conforming mesh... It is an option when you compute mesh. Change the pull down to "geometry and mesh" and select the parts where you want to keep the mesh.

That is Compute mesh > Volume Meshing > Input > Use Existing Mesh Parts? Then these mesh parts will be skipped during octree mesh generation? And octree also ensures that the mesh is conformal with the already existing mesh.

Originally Posted by PSYMN

If you assign prism to a surface, like that tire, it will stair step off as it approaches the edge. It does this to prevent a solution where you have all the prisms ending along one plane, particularly very thin prisms with pyramids sticking out into the tetra volume. The best solution is to include the side surfaces in your prism selection. Then prism will be full on the surface you want and will taper off on the adjacent surface.

I need to create two surfaces perpendicular to the wheel surface?