Hi,
We are experimenting with inserting particles into a periodic cell between pre-existing particles using fix pour. We have found that fix pour can insert particles over the x and y periodic boundaries without overlapping particles on the other side of the boundary, but is unable to do this with the z-boundary. The code is below (tested with the latest stable release), I can provide the input data by email or send to the list (122kb). From the dump file you will see that particles close to the z-boundary have very high stresses as they overlap on placement.
I note that the issue with the side boundaries was noted before https://lammps.sandia.gov/threads/msg43509.html and I appreciate that fix pour was not probably not intended for use with a z periodic boundary, but any help fixing this would be greatly appreciated.
Best wishes,
Tom Shire
Initialisation ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
units si
boundary p p p
atom_style sphere
dimension 3
newton on
comm_modify mode single vel yes
Create particles ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
read_data Particle_Coordinates.lj
neighbor 1e-3 bin
neigh_modify delay 0 every 1
pair_style gran/hooke/history 1e8 NULL 50.0 NULL 0.5 1
pair_coeff * *
timestep 1.5e-9
run_style verlet
fix 3 all nve/sphere
fix grav all gravity 0.0 vector 0 0 -1 # set to zero so particles don’t move in periodic cell
variable step equal step
variable xlength equal lx
variable ylength equal ly
variable zlength equal lz
variable particles equal atoms
variable steps equal 5
compute stress all stress/atom NULL pair
compute 5 all stress/atom NULL pair
dump 1 all custom 1 dump.stress id x y z diameter c_stress[1] c_stress[2] c_stress[3]
run 1
####################### ADD NEW PARTICLES #########################
region myreg1 block 0 1.60626 0 1.60626 0 0.5
fix pour1 all pour 1000 1 413554 region myreg1 diam one 0.01 dens 2650 2650
run 1