Creates more particles when iteration increases

Submitted by laudari on Fri, 01/29/2021 - 07:49

Hello LIGGGHTS forum, I really appreciate your help.
I have been trying to do a simple simulation. Recently I noticed that more particles are created when iteration is increase. I actually need only one particle in my dump file. I have included my script and dump.data file here with few questions.
Could you kindly help me?

Scripts:
# Initialize

atom_style granular
atom_modify map array
###########################################################################################
#Describe boundary

boundary f f f
newton off
communicate single vel yes
units si

####################################################################################################################
#Declare domain number of materials as domain

region domain block -0.5 0.1 -0.2 0.2 -0.4 0.15 units box
create_box 1 domain

#####################################################################################################################
#Neighbor listing

neighbor 0.001 bin
neigh_modify delay 0

#####################################################################################################################
## Material and interaction properties

fix m1 all property/global youngsModulus peratomtype 5.e6
fix m2 all property/global poissonsRatio peratomtype 0.4
fix m3 all property/global coefficientRestitution peratomtypepair 1 0.2
fix m4 all property/global coefficientFriction peratomtypepair 1 0.4
fix m5 all property/global k_finnie peratomtypepair 1 1.0
fix m6 all property/global coefficientRollingFriction peratomtypepair 1 0.01
#######################################################################################################################
#New pair style, define physics

pair_style gran model hertz tangential history #Hertzian without cohesio
pair_coeff * *

#############################################################################################
#Time step

timestep 0.00001

##############################################################################################
# Integrator and gravity

fix integrate all nve/sphere
fix gravi all gravity 9.81 vector 0.0 0.0 -1.0
#############################################################################################
#Particle insertion

fix cad all mesh/surface/stress file meshes/simple_chute.stl type 1 wear finnie
fix inface all mesh/surface file meshes/insertion_face.stl type 1
fix granwalls all wall/gran model hertz tangential history mesh n_meshes 1 meshes cad
fix mass all massflow/mesh mesh inface count once point_at_outlet 0. 0. 0.

#######################################################################################################
# Particle properties

fix pts1 all particletemplate/sphere 15485863 atom_type 1 density constant 20 radius constant 0.0015

#Describe the composition of the particle distribution
fix pdd1 all particledistribution/discrete 32452843 1 pts1 1.0

##############################################################################################################

#Define insertion region, velocity for particle

group nve_group region domain
region bc cylinder z 0.0 0.0 0.015 0.05 0.12 units box
fix 1 all nve velocity all pts1 NULL 0.5 NULL units box

##############################################################################################################

#particle insertion

fix ins nve_group insert/pack seed 32452867 distributiontemplate pdd1 insert_every 1 overlapcheck yes all_in yes particles_in_region 1 region bc

################################################################################################################
compute 1 all erotate/sphere
thermo_style custom step atoms ke c_1 vol
thermo 1000
thermo_modify lost ignore norm no
compute_modify thermo_temp dynamic yes

##########################################################################################################################
run 100
#########################################################################################################################

dump dmp all custom/vtk 200 particleB/chute_*.vtk id type type x y z ix iy iz vx vy vz fx fy fz omegax omegay omegaz radius
dump dumpstress all mesh/gran/VTK 200 particleB/mesh_*.vtk stress wear cad
dump dmp0 all custom 10 particleB_dump/dump*.data id type type x y z vx vy vz fz fy fz
#################################################################################################

#unfix ins
run 1000000 upto

unfix ins

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

dump.data file:
==============

when it started - step 10:
ITEM: TIMESTEP
10
ITEM: NUMBER OF ATOMS
1
ITEM: BOX BOUNDS ff ff ff
-0.5 0.1
-0.2 0.2
-0.4 0.15
ITEM: ATOMS id type type x y z vx vy vz fz fy fz
1 1 1 0.00162983 0.00252669 0.052531 0 0 -0.0018639 -2.77371e-06 0 -2.77371e-06

-------------------------------------------------------------------------------------------------------------------------------------------------------
later on - step 30000

ITEM: TIMESTEP
37970
ITEM: NUMBER OF ATOMS
10
ITEM: BOX BOUNDS ff ff ff
-0.5 0.1
-0.2 0.2
-0.4 0.15
ITEM: ATOMS id type type x y z vx vy vz fz fy fz
7 1 1 -0.076216 -0.00267228 0.134048 -0.393453 -0.0808271 0.476712 -2.77371e-06 0 -2.77371e-06
2 1 1 -0.456892 -0.00964288 -0.35402 -1.23492 -0.0131475 -1.5668 -2.77371e-06 0 -2.77371e-06
3 1 1 -0.378195 -0.00222328 -0.274897 -1.21475 0.0285308 -0.944636 -2.77371e-06 0 -2.77371e-06
5 1 1 -0.343139 0.0152948 -0.251435 -1.03138 -0.0476859 -0.636269 -2.77371e-06 0 -2.77371e-06
4 1 1 -0.17683 -0.00211806 -0.180424 -1.07222 -0.0348454 -0.428653 -2.77371e-06 0 -2.77371e-06
6 1 1 -0.143029 -0.00641894 -0.166236 -0.919677 -0.00845824 -0.381421 -2.37829e-07 6.4584e-08 -2.37829e-07
8 1 1 -0.0224919 -0.00848567 -0.115333 -0.595621 0.0874951 -0.245941 -2.23721e-07 7.00177e-09 -2.23721e-07
9 1 1 -0.0168881 0.00603514 -0.0223347 -0.422936 -0.0272437 1.79791 -2.77371e-06 0 -2.77371e-06
10 1 1 0.00935496 -0.00117298 -0.0777684 0 0 -1.73058 -2.77371e-06 0 -2.77371e-06
11 1 1 -0.0106077 0.00555359 0.0520806 0 0 -1.03191 -2.77371e-06 0 -2.77371e-06
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

My questions are:

1) Why number of atoms are increasing? I only need 1 atom in each dump.data. Is it possible to make onle 1 atom in each steps?
2) Is it possible to give time while inserting particles so that one leaves domain and another falls down?

Thank you so much in advanced.

laudari | Sun, 01/31/2021 - 17:05

Thank you for your reply. I have to create more than 50 flows one by one. Which means I have to drop particle one by one. When I changed to once it only drops 1 particle in entire simulation.
How do I fixed it ?
Thank you