[bruce21]

Hi CFD community,

I am using snappyHexMesh to refine my axisymmetric mesh (which uses a wedge boundary condition). I created this wedge domain using Gmsh. When I try refining the mesh, I see that the wedge boundaries lose their planarity. I see this is because snappy is refining the mesh in Y axis (around the axis of symmetry) also. Please see the attached dictionary file.

I need to refine the mesh only in X and Z direction, but not Y. I realized that refineMesh can do this, but the resulting mesh isn't satisfactory.

So, is there a way to specify directionality (refine only in specified axis) while using snappyHex for refinement?

Thanks in advance!

[LuckyTran]

Not in snappy, no. Snappy is not a mesher, it is a tool that makes a mesh snappy. Snappy is also not a tool for refining a mesh.

Is your domain a simple wedge? If so, return to the original blockMesh, you don't need snappy. If you have a wedge with a car inside it then:

Two other ideas you may like to try
1) Increase the resolution in the X and Z direction in the original blockMesh. Then snap it.
2) Scale the mesh in the Y direction smaller. Run snappy. Then scale the Y-dimension back up.

[AtoHM]

The ESI version of snappyHexMesh does support directional refinement.

[bruce21]

Originally Posted by LuckyTran

Not in snappy, no. Snappy is not a mesher, it is a tool that makes a mesh snappy. Snappy is also not a tool for refining a mesh.

Is your domain a simple wedge? If so, return to the original blockMesh, you don't need snappy. If you have a wedge with a car inside it then:

Two other ideas you may like to try
1) Increase the resolution in the X and Z direction in the original blockMesh. Then snap it.
2) Scale the mesh in the Y direction smaller. Run snappy. Then scale the Y-dimension back up.

Hi LukcyTran,

I don't have an object for thr mesh to snap on. But, I created the mesh using GmsH and it's kind of a hard deal to do add refinement regions by manually creating blocks (which you probably already know). That is why I wanted to use a refinement utility within openfoam.

However, thanks for the suggestions. I will go back to using a blockMesh and try out these methods if I couldn't find a (easier) solution soon.

[bruce21]

Originally Posted by AtoHM

The ESI version of snappyHexMesh does support directional refinement.

Hi AtoHM,

Thanks for the reply! That's good news . If possible, can you share a sample snappyHex dict file with the directional refinement classes in it? I'll try installing the ESI version and give it a try.

[Yann]

Hello,

Here are the release notes when directional refinement has been introduced in OpenFOAM-v1806:
https://www.openfoam.com/news/main-n...pre-processing

A stretching feature also appeared in the next release (OpenFOAM-v1812):
https://www.openfoam.com/news/main-n...pre-processing

Any version from ESI released after v1812 should have these features.

[bruce21]

Originally Posted by Yann

Hello,

Here is the release notes when directional refinement has been introduced in OpenFOAM-v1806:
https://www.openfoam.com/news/main-n...pre-processing

A stretching feature also appeared in the next release (OpenFOAM-v1812):
https://www.openfoam.com/news/main-n...pre-processing

Any version from ESI released after v1812 should have these features.

Hi Yann,

That is superb! Thank you so much for the link. On first glance, it looks like that is exactly what I was looking for.