[ICEM] Tetra/Prism Mesh with Translational Periodicity

siw · November 12, 2013, 04:54

Hi,

I'm making a tetra/prism mesh of a rectangular fluid domain for an external aerodynamics simulation in CFX. I would like the two side faces of the domain to have identical surface meshes (their mesh parameters are the same) so that I can make their boundary conditions in CFX to be a translational periodic interface, rather than use symmetrical boundary conditions.

Is this possible with the global periodicity option? I find the best way to make tetra/prism meshes is to make an octree volume mesh, delete the volume cells, smooth, make a Delaunay volume mesh, smooth, make the prism layers and smooth. Will the periodicity be respected with this method? The User Guide says that periodicity with Delaunay in not applicable.

Thanks

Far · November 12, 2013, 05:17

In your case you are going to make Delaunay mesh from the surface mesh. And surface mesh is obtained from the octree method and octree method respects periodicity!!!

Now the question is that does delaunay change the surface mesh in the process? If no then you have perfect mesh.

siw · November 12, 2013, 05:35

I should have also said that the base of the rectangular domain will be a no-slip wall, so it will have prisms on it. So will surface mesh on the sides respect translational periodicity with the prism layers are built up from the wall?

Far · November 12, 2013, 11:00

But I have observed that in process, prism mesh (unless you play with advanced parameters) changes the surface mesh little bit. But that cab be corrected in the edit mesh menu. I haven't tried this all but i am going to do it on the 90 deg solid from cylinder.

siw · November 20, 2013, 07:22

Does ICEM respect periodicity of surface meshes when smoothing is conducted? For example, if we smooth a mesh will ICEM make sure to movement of nodes on periodic faces is identical.

After some testing I can answer my own question. Yes, it does respect periodicity when smoothing and making prism layers.

Hoyskipoyski · April 9, 2015, 12:05

Anyone got some tips regarding the smoothing of a tetra mesh with rotational periodicity?

I mostly find the bad elements where periodic faces meet with non periodic faces. Of course one can move the bad periodic node, improve the specific element and then adjust the other node by using the repair/make periodic tool, but that's not really automated.
Any hints?

timotie87 · March 26, 2020, 16:16

Hello, I am doing something similar as described in the first post.

Did you come up with a way to accomplish this?

I think I will try

1. Octree mesh (no prism layers)
2. Delete volumes
3. Smooth surface mesh
4. Delaunay volume mesh
5. Generate prism layers

Will the prism layers generated after the Delaunay volume mesh respect the rotational periodicity?

November 12, 2013, 04:54	Tetra/Prism Mesh with Translational Periodicity	#1
siw Senior Member Stuart Join Date: Jul 2009 Location: Portsmouth, England Posts: 739 Rep Power: 26	Hi, I'm making a tetra/prism mesh of a rectangular fluid domain for an external aerodynamics simulation in CFX. I would like the two side faces of the domain to have identical surface meshes (their mesh parameters are the same) so that I can make their boundary conditions in CFX to be a translational periodic interface, rather than use symmetrical boundary conditions. Is this possible with the global periodicity option? I find the best way to make tetra/prism meshes is to make an octree volume mesh, delete the volume cells, smooth, make a Delaunay volume mesh, smooth, make the prism layers and smooth. Will the periodicity be respected with this method? The User Guide says that periodicity with Delaunay in not applicable. Thanks

November 20, 2013, 07:22		#5
siw Senior Member Stuart Join Date: Jul 2009 Location: Portsmouth, England Posts: 739 Rep Power: 26	Does ICEM respect periodicity of surface meshes when smoothing is conducted? For example, if we smooth a mesh will ICEM make sure to movement of nodes on periodic faces is identical. After some testing I can answer my own question. Yes, it does respect periodicity when smoothing and making prism layers. Last edited by siw; November 20, 2013 at 09:04.

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November 12, 2013, 05:17		#2
Far Senior Member Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,558 Blog Entries: 6 Rep Power: 54	In your case you are going to make Delaunay mesh from the surface mesh. And surface mesh is obtained from the octree method and octree method respects periodicity!!! Now the question is that does delaunay change the surface mesh in the process? If no then you have perfect mesh.

November 12, 2013, 05:35		#3
siw Senior Member Stuart Join Date: Jul 2009 Location: Portsmouth, England Posts: 739 Rep Power: 26	I should have also said that the base of the rectangular domain will be a no-slip wall, so it will have prisms on it. So will surface mesh on the sides respect translational periodicity with the prism layers are built up from the wall?

November 12, 2013, 11:00		#4
Far Senior Member Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,558 Blog Entries: 6 Rep Power: 54	But I have observed that in process, prism mesh (unless you play with advanced parameters) changes the surface mesh little bit. But that cab be corrected in the edit mesh menu. I haven't tried this all but i am going to do it on the 90 deg solid from cylinder.

April 9, 2015, 12:05		#6
Hoyskipoyski New Member Simon Harbeke Join Date: Nov 2014 Posts: 11 Rep Power: 11	Anyone got some tips regarding the smoothing of a tetra mesh with rotational periodicity? I mostly find the bad elements where periodic faces meet with non periodic faces. Of course one can move the bad periodic node, improve the specific element and then adjust the other node by using the repair/make periodic tool, but that's not really automated. Any hints?

March 26, 2020, 16:16		#7
timotie87 New Member Tim Join Date: May 2016 Posts: 11 Rep Power: 10	Hello, I am doing something similar as described in the first post. Did you come up with a way to accomplish this? I think I will try 1. Octree mesh (no prism layers) 2. Delete volumes 3. Smooth surface mesh 4. Delaunay volume mesh 5. Generate prism layers Will the prism layers generated after the Delaunay volume mesh respect the rotational periodicity?