| Tobi |
March 30, 2017 07:43 |
symmetryPlane in sHM
Hi everybody,
I have a question to you. Maybe one got to the same problem. I am meshing a complex geometry with sHM but I have problems with the symmetry planes. The faces are not 100% aligned to the patch normal and therefore I get e.g. displacements in y direction based on the surface normal direction.
Question 1
- Is there a way to flatten the symmetry patches in order that all points are aligned within one plane (like flattenMesh for 2D).
Note 1
- symmetry vs. symmetryPlane
- I read that people just change it without thinking about the differences. The difference should be:
- symmetryPlane has to be really flat and one single patch (no multi patch assembly)
- symmetry can be used for non-100% aligned flat patches and multi patch assemblies
- I got this from https://openfoam.org/release/2-3-0/numerics/
However, using the symmetry BC in my simulation lead to the problem that I get motion in the direction I want to constrain (like y-direction). This is based on the fact that I do not get a 100% aligned flat patch after snapping with snappyHexMesh.
Question 2
- Does anybody know how to get a flat patch using sHM
- Maybe there is a tool out which can be used to flatten a patch (like flattenMesh for 3D)
- I was expecting that after defining the patchType in the snappyHexMeshDict to be symmetry or symmetryPlane, the meshing application takes care of adjusting the points.
assign the symmetryPlane patch type. I get the problem, that the application tells me the following:
Code:
Symmetry plane 'sym1' is not planar.
At local face at (0.00702909 0.00026875 0.0282749) the normal (1 3.22739e-15 1.60222e-15) differs from the average normal (0.428571 5.18688e-16 -6.34413e-17) by 0.326531
Either split the patch into planar parts or use the symmetry patch type
However, the normal vector at point (0.00702909 0.00026875 0.0282749) is fine. It should direct to the x direction which it probably do but I have no idea why it is complaining about that point because it is not on the sym1 patch. |
