Hello,
I am trying to model flow of grains through a slit under confining pressure (imagine sand grains in a fracture confined under a certain pressure). The way I'm doing this is by creating two rigid walls made of atoms arranged in a lattice with a force applied to each atom. However, once I create the lattice and apply the rigid command, all atoms in the lattice are returned with NaN or -NaN in the dump files after the first step. Code is attached.
I know I'm just missing a simple step. Ideas?
Thanks,
Roman
atom_style granular
atom_modify map array
boundary f f f
newton off
communicate single vel yes
units si
region reg block -8.5e-4 8.5e-4 -2.7e-3 2.7e-3 -5e-5 2.7e-3 units box
region inbox block -7.5e-4 7.5e-4 -2e-3 -0.5e-3 0.5e-3 2e-3 units box
region outbox block -7.9e-4 7.9e-4 0 2.5e-3 0 2.5e-3 units box
region leftwall block -8e-4 -7.75e-4 -2.5e-3 0 0 2.5e-3 units box
region rightwall block 7.75e-4 8e-4 -2.5e-3 0 0 2.5e-3 units box
create_box 1 reg
neighbor 1e-3 nsq
neigh_modify delay 0
#Material properties required for new pair styles
fix m1 all property/global youngsModulus peratomtype 7.e10
fix m2 all property/global poissonsRatio peratomtype 0.20
fix m3 all property/global coefficientRestitution peratomtypepair 1 0.3
fix m4 all property/global coefficientFriction peratomtypepair 1 0.5
fix m5 all property/global coefficientRollingFriction peratomtypepair 1 0
#New pair style
pair_style gran/hertz/history 3 0 #Hertzian without cohesion
pair_coeff * *
#Create bounding walls
fix zwall all wall/gran/hertz/history 1 0 zplane -5e-5 2.7e-3 1
fix ywall all wall/gran/hertz/history 1 0 yplane -2.7e-3 2.7e-3 1
fix xwall all wall/gran/hertz/history 1 0 xplane -8.5e-4 8.5e-4 1
fix ybarrier all wall/gran/hertz/history 1 0 yplane 0 NULL 1
timestep 1e-8
fix ts_check all check/timestep/gran 1000 0.2 0.2
#Create wall lattice
lattice sc 5e-5
create_atoms 1 region leftwall units box
group leftwall_atoms region leftwall
create_atoms 1 region rightwall units box
group rightwall_atoms region rightwall
group walls union rightwall_atoms leftwall_atoms
set group walls diameter 5e-5 omegax 0 omegay 0 omegaz 0 density 2650
#Make the walls rigid
fix 1 walls rigid group 2 leftwall_atoms rightwall_atoms
neigh_modify exclude group leftwall_atoms leftwall_atoms check no
neigh_modify exclude group rightwall_atoms rightwall_atoms check no
#Apply force to the walls
fix shmin leftwall_atoms setforce 5000 0 0
fix shmin2 rightwall_atoms setforce -5000 0 0
fix ts_check all check/timestep/gran 1000 0.2 0.2
#fix gr all gravity 5000 vector -1 0 -1
#output settings, include total thermal energy
compute 1 all erotate/sphere
thermo_style custom step atoms ke c_1 vol
thermo 40
thermo_modify lost ignore norm no
compute_modify thermo_temp dynamic yes
dump dmp_paraview all custom 40 ./post/dump_confine_large_23_*.liggghts id type type x y z ix iy iz vx vy vz fx fy fz omegax omegay omegaz radius
dump dmp_walls walls custom 40 ./post/dump_wall_*.liggghts id type type x y z ix iy iz vx vy vz fx fy fz omegax omegay omegaz radius
run 500000