Meshing a truncated cyliner by extruding a surface mesh

[ews-ffarella]

Hello,
I would like to generate a mesh based by extruding a surface mesh (topography). The final volume should be a vertical cylinder (truncated by the input surface mesh), but it could also be a cube. This is for a simulation of the atmospheric boundary layer.

see example

Could you give me pointers about how to do it? I guess I will use the python interface.

Also, would it be possible to perform the extrusion in 2 steps. Once with a constant stretch factor (close to 1), and then with a larger one?

Thank you very much for providing the community with such a great tool ;)

[sseraj]

Unfortunately, pyHyp cannot handle this use case because the farfield boundary shape cannot be prescribed when using hyperbolic marching.

[ews-ffarella]

Thanks for the reply. What would be the shape of the produced mesh?

[sseraj]

The farfield will look like a smoothed version of the input surface. For our most common use cases, the farfield looks spherical because we extrude far away from the surface.

[ews-ffarella]

Thank you! I might still give it a try and constrain the mesh manually after. The normals at the boundaries are pointing strictly upwards, so it might help.

Would this example be the closest to what I need (3d extrusion)?

https://github.com/mdolab/pyhyp/blob/main/examples/sphere/runSphere.py

[sseraj]

I think this example might be closer to what you are looking for https://github.com/mdolab/pyhyp/blob/main/examples/plate/runPlate.py. You should be able to set the BC option to keep the sides of the mesh cylindrical.

[ews-ffarella]

Thanks, I have played around with the plate example.

I have tried with an STL converted to CGNS using paraview, but it get an cgio_open_file:invalid file type error.
Does the input geometry need to be all quads?

OK, I think you can only get structured meshes and input, right?

[ews-ffarella]

Amazing!

With full control of the 2D grid:

You have no idea how long I had been searching for this. Thank you soooooo much 😄