is there a way to implement a moving window calculation, i.e. to make atoms enter simulation box from one side, move through the box and go out from the opposite boundary, where they are destroyed?
I think a combination of fix deposit (with velocities set) and fix evaporate (with a large N) with appropriate regions set might help. I’ve never used it, but hope this helps.
It is supposed that inside the box will be a (initially) plane reaction front, and we are interested in whether it will change its shape due to instabilities. So we need a large cell in the directions normal to that of the front propagation and large simulation time, and it would be too costly to simulate non-reacting (yet) matter, too.
I think there is a typo in 16th line of SHOCK/fix_append_atoms.cpp. LAMMPS could not recognize the fix until append_atoms is replaced with append/atoms in that line.