Fix curved symmetries

[bigfooted]

Proposed Changes

Give a brief overview of your contribution here in a few sentences.
For nodes that are shared by 2 or more curved symmetries (usually Euler walls) we do not need to apply Gram Schmidt orthogonalization to correct the face normals. Instead, we need to add the normals to retrieve the same normals as if these faces were merged. For straight symmetries (could be euler walls as well but usually symmetry planes) we always perform GSO when nodes are shared with another symmetry (straight or not).

Related Work

Resolve any issues (bug fix or feature request), note any related PRs, or mention interactions with the work of others, if any.

Reported on slack:
"Hi all. I am running a 3D euler simulation on a vehicle. I build the mesh in gmsh. the vehicle surface is composed by several gmsh surfaces. initially I had 1 boundary condition for the whole vehicle surface, with marker name "wall", in which I applied a marker Euler.for mesh adaptation purposes, I need one of the gmsh surfaces to have a different marker name, called "no_adapt", in which I also apply a marker Euler.So I have MARKER_EULER = (wall) vs. MARKER_EULER = (wall, no_adapt)with 1 marker, the surface solution is smooth in the region of interest. with 2 markers, I would expect the same outcome, since I use the same BC, simple divide it with 2 different names. However, the solution at the interface between the two markers goes really weird.I already checked the mesh generation several times and I cannot find any issue on the mesh generation end.So I'm left with wondering if the problem could be on the SU2 side ... Anyone has any feedback on this?"

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[rois1995]

Is this related to the problems I was encountering in #2390?

[bigfooted]

Is this related to the problems I was encountering in #2390?

No, this is a fix for nodes that are shared by 2 curved Euler walls. For your issue, I am not sure what the root cause is. Did you work more on this?

[rois1995]

Unfortunately not, I am trying to close some other PR that I have open from long ago. I guess it is still a problem with normals in the point where the slope changes direction. I will try to have a look into it whenever I can.

[pcarruscag]

We may want to fabricate a case that has all these things, 3 merged symmetries, intersecting a plane.

[bigfooted]

We may want to fabricate a case that has all these things, 3 merged symmetries, intersecting a plane.

Like the flow around a wall mounted cube, with a vertical symmetry, and then split the square cube surfaces diagonally.

[pcarruscag]

Maybe a cylinder otherwise all surfaces are flat.

[bigfooted]

3D flow over wall-mounted cylinder (Re=1)

[pcarruscag]

How many shared symmetries does it have?

[bigfooted]

I changed the 'flow over wall mounted cylinder' such that the leading edge lower corner now has 3 Euler walls and 1 symmetry. So basically every side is a symmetry or an Euler wall except inlet and outlet.
The trailing edge has 2 Euler walls and 1 symmetry

[bigfooted]

The solution looks bit wobbly because of the course mesh, but there is now jump over the interfaces.

[bigfooted]

During convergence, there are sometimes some peaks in the residual plot, caused by the 4-symmetry points:

But the residuals recover quickly and in the end it converges. Note that the mesh is really bad in that corner, with very skewed cells.

[pcarruscag]

Let's hope it's good enough for some months without symmetry issues. Can you add the case? I can update the residuals again.

[bigfooted]

I changed some settings (INC_NS -> INC_EULER) and convergence looks smooth now, I will update...