Rotation boundary condition

User Support
1

Hello,

I need a little help to improve my core geometry, please.

I’d like to use a special boundary condition on a surface : I’ve a geometry where I can take advantage of a punctual central symmetry (half core) to accelerate calculations.

I’ve tried to draw it (simplify !) in the following picture (a CYLZ cut with a YPLANE). For example, if a particle comes out of a position x with a vector (i, j, k), I want it to enter from a position -x with a vector (-i, -j, k).

openmc_bo
openmc_bo1011×494 20.4 KB

Is there a mixture of both periodic and reflective boundary conditions to do it ? I’ve some difficulties to imagine how to do it…

Can I consider a surface as both entry and exit for a periodic boundary condition : border.periodic_surface = border ?

Or is a specific development needed (rotation boundary condition ?) ?

Thank you in advance for your answer.

Regards

Julien

2

Hi Julien,

I also had similar question. I have two ideas as shown in the figure below.

  1. Use a reflective plane X=Y to cut the core
  2. Or joint two 1/4 core to make a pair of periodic planes

I’m not sure whether the second idea is available. Looking forward to others’ suggestion.

825df6844fb90189f08707fe0dcf0eb95e5004be_2_690x337
825df6844fb90189f08707fe0dcf0eb95e5004be_2_690x337690×696 46.2 KB

3

The reflective solution along x=y is probably your best bet. I don’t see how the second option here would work. There is a pull request adding supporting for general rotational periodic conditions, but in this case because plane 1 and plane 2 are effectively the same plane, it likely won’t work.