[snappyHexMesh] Snappy. Mesh region between 2 concentric stls

be_inspired · May 16, 2014, 10:46

Hi all,

I am trying to mesh the region between 2 stls.
Originally there were 2 meshes. The bigger one in which some cells were removed using subsetMesh and and internal Mesh. The objective is to create new grid in the region between both meshes and so, to obtain a unique mesh but keeping the original ones. After snappy, the next step would be to merge all meshes and stich the meshes to delete all internal faces.

I have 2 stls. The geometries were obtained using foamToSurface+surfaceSplitByPatch.

Could you give me some guidance about how to proceed with snappy or if the procedure is not valid?

Best Regards
Marcelino

Eloise · May 16, 2014, 11:44

Hi Marcelino,
Stitching meshes which have several common patches doesn't seems to be possible. It seems to be only possible when the have 1 common patch (such as a sphere or a cylinder). Please see the following post where this issue is discussed:
when can stitchMesh be used?
I hope you find an alternative approach!
Regards,
Eloïse

be_inspired · May 16, 2014, 15:21

Ok, my approach would not work because the patch would be of arbitrary shape depending on original mesh and what cell would be removed.

I am trying to find a method to introduce a very refined mesh and to use snappy to smooth the transition between original grid and new grid. It is not a chimera grid but some interesting possibilities could be obtained introducing elements in any location of the mesh without re-meshing the whole mesh or thinking about where to locate the interfaces before hand.

It could be other option to manage moving elements. The secondary mesh can be moved along space and a new mesh of transition is developed by snappy every time step. The perfect solution would be to use overset grids but.... there is a cost.

Best Regards
Marcelino

be_inspired · May 20, 2014, 14:21

Could it be possible to use a mesh generated with ICEMHEXA as the initial mesh for snappyhexMesh? In this way:
1. the inner stl could be introduce to refine and snap to surface
2. Merge the secondary mesh
3. Maybe to use ggi interface between both meshes.

I only want a well refined disk and wake region to use rotorDiskSource or actuator line Source with the rotor Disk in any location/direction.

What do you think?

May 16, 2014, 15:21		#3
be_inspired Senior Member M. Montero Join Date: Mar 2009 Location: Madrid Posts: 155 Rep Power: 17	Ok, my approach would not work because the patch would be of arbitrary shape depending on original mesh and what cell would be removed. I am trying to find a method to introduce a very refined mesh and to use snappy to smooth the transition between original grid and new grid. It is not a chimera grid but some interesting possibilities could be obtained introducing elements in any location of the mesh without re-meshing the whole mesh or thinking about where to locate the interfaces before hand. It could be other option to manage moving elements. The secondary mesh can be moved along space and a new mesh of transition is developed by snappy every time step. The perfect solution would be to use overset grids but.... there is a cost. Best Regards Marcelino Last edited by be_inspired; May 20, 2014 at 06:27.

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May 16, 2014, 11:44		#2
Eloise Senior Member Eloïse Join Date: Jul 2012 Location: Trondheim, Norway Posts: 113 Rep Power: 14	Hi Marcelino, Stitching meshes which have several common patches doesn't seems to be possible. It seems to be only possible when the have 1 common patch (such as a sphere or a cylinder). Please see the following post where this issue is discussed: when can stitchMesh be used? I hope you find an alternative approach! Regards, Eloïse

May 20, 2014, 14:21		#4
be_inspired Senior Member M. Montero Join Date: Mar 2009 Location: Madrid Posts: 155 Rep Power: 17	Could it be possible to use a mesh generated with ICEMHEXA as the initial mesh for snappyhexMesh? In this way: 1. the inner stl could be introduce to refine and snap to surface 2. Merge the secondary mesh 3. Maybe to use ggi interface between both meshes. I only want a well refined disk and wake region to use rotorDiskSource or actuator line Source with the rotor Disk in any location/direction. What do you think?