Periodic boundary conditions

[Cabaset Elise]

Hi,

I am currently using GeoDict for particle tracking simulations, and I have a question regarding the implementation of periodic boundary conditions in this context.

The user guide states: "With Periodic boundary conditions, the particle will leave the domain and reappear on the opposite site." I would like to understand how this is handled mathematically, especially in the case of non-periodic geometries.
Specifically: When a particle exits through one boundary , how is its re-injection position on the opposite face determined? If a solid structure (e.g., a fiber) happens to occupy the re-injection location on the opposite face, how does GeoDict handle this situation?

Thank you in advance for your clarification

[Jürgen Becker]

Dear Elise,

if there is a solid structure on the opposite face, the particle will collide with this structure - it may bounce off or stick to the fiber.
You can imagine the 3D structure to continue with periodic copies of itself. Thus, a particle cannot leave the domain, if there is a solid on the opposite face.

Best Regards,
Jürgen