[FLASH-USERS] BCs for rotational symmetry in Flash3

[Dave]

Hi,

I'm trying to figure out how to how to impose 4-fold rotational symmetry 
boundary conditions in flash3 - e.g. the 3D simulation box is 1/8 of the 
total volume, and the gas that flows out of the x=0 axis flows back into 
the y=0 axis (with velocities rotated by 90 degrees).

Looking through the code, it appears the outflow, diode and reflective 
boundary conditions are done on a block-by-block basis, while periodic 
boundary conditions are done by just modifying the gid array.

However, I can't see an easy way to implement rotational symmetry with 
either of these methods. Before I dive in and start doing things the 
hard way, I was wondering if anyone has done this before and maybe has 
some tips on how to apply these boundary conditions in a "natural" way 
to Flash's architecture?

Cheers,
David