Particles are falling outside of domain.

Submitted by laudari on Fri, 01/08/2021 - 08:06

I am trying to run a simple simulation with a mesh file which is available in example as simple_chute.stl.
Now I am able to run simulation after changing the boundary to m m m but all of my particles are falling outside of domain.
Can anyone help me to fix this problem?

This is my script:

###############################################
# Example of LIGGGHTS #
# Flow only two particles in a plane surface #
###############################################

# Initialize

atom_style granular
atom_modify map array

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

boundary m f f
#boundary f f f

##################################################################################################################
#Determines whether or not to calculate pairwise interactions on each processor; best to leave off #for a DEM simulation where only short-range interactions are presnet

newton off
communicate single vel yes
units si

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

# Specifies a region called domain for that describes the bounds of the domain
#block args = xlo xhi ylo yhi zlo zhi

region domain block -0.2 0.0 -0.2 0.2 -0.4 0.3 units box

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

# create_box N reion-id

create_box 1 domain

#####################################################################################################################
#neighbor 0.002 bin
neighbor 0.001 bin
neigh_modify delay 0

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

#When using multiple materials,the properties for each material are specified sequentially
#Material properties required for new pair styles

fix m1 all property/global youngsModulus peratomtype 5.e6
fix m2 all property/global poissonsRatio peratomtype 0.45
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 k_finnie peratomtypepair 1 1.0

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

#New pair style

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

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

#Time step for the simulation. Typically try to keep this less than or equal to 20% of the #Rayleigh time.

timestep 0.00001

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

#fix 1 all nve/sphere
#fix nveint all nve/sphere

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

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

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.

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

fix pts1 all particletemplate/sphere 15485863 atom_type 1 density constant 200 radius constant 0.0025
fix pts2 all particletemplate/sphere 15485867 atom_type 1 density constant 200 radius constant 0.0025

#Describe the composition of the particle distribution
fix pdd1 all particledistribution/discrete 32452843 2 pts1 0.3 pts2 0.7

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

#region and insertion
group nve_group region domain
region bc block -0.2 0.0 -0.2 0.2 -0.4 0.3 units box

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

#particle insertion

fix ins nve_group insert/pack seed 32452867 distributiontemplate pdd1 insert_every 2 overlapcheck yes all_in yes vel constant 0.0 0.0 0.0 particles_in_region 1 region bc

#run 5000
#unfix ins1

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

#output settings, include total thermal energy
compute 1 all erotate/sphere

# Describe which quantities are to be printed in the logfile

thermo_style custom step atoms ke c_1 vol

#How often to write thermodynamic quantities

thermo 1000
thermo_modify lost ignore norm no

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

#Run the time step check over 1 time step
#insert the first particles so that dump is not empty
run 1

#########################################################################################################################
dump dmp all custom/vtk 200 result/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 result/mesh_*.vtk stress wear cad

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

#restart 5000 restart/restart1*.bin

run 100000 upto
unfix ins

Error, I get when I use f f f boundary

ERROR: Mesh (id cad): 683 mesh elements have been lost / left the domain.
Please use 'boundary m m m' or scale/translate/rotate the mesh or change its dynamics
FYI: center of mass of mesh including scale/tranlate/rotate before cutting out elements is -0.148131 / 0.003869 / -0.127528
simulation box x from -0.200000 to 0.000000 y from -0.200000 to 0.200000 z from -0.400000 to 0.300000
center of mass of mesh after cutting out elements outside simulation box is is -0.098473 / 0.011222 / -0.102990
(gives indication about changes in scale/tranlate/rotate necessary to make simulation run)
(/build/liggghts-YO7u74/liggghts-3.8.0+repack1/src/multi_node_mesh_parallel_I.h:605)
(/build/liggghts-YO7u74/liggghts-3.8.0+repack1/src/multi_node_mesh_parallel_I.h:605)
,

laudari | Fri, 01/08/2021 - 08:53

ERROR: Mesh (id cad): 683 mesh elements have been lost / left the domain.
Please use 'boundary m m m' or scale/translate/rotate the mesh or change its dynamics
FYI: center of mass of mesh including scale/tranlate/rotate before cutting out elements is -0.148131 / 0.003869 / -0.127528
simulation box x from -0.200000 to 0.000000 y from -0.200000 to 0.200000 z from -0.400000 to 0.300000
center of mass of mesh after cutting out elements outside simulation box is is -0.098473 / 0.011222 / -0.102990
(gives indication about changes in scale/tranlate/rotate necessary to make simulation run)
(/build/liggghts-YO7u74/liggghts-3.8.0+repack1/src/multi_node_mesh_parallel_I.h:605)
(/build/liggghts-YO7u74/liggghts-3.8.0+repack1/src/multi_node_mesh_parallel_I.h:605)

deepakpawar.2310 | Fri, 01/08/2021 - 18:48

Hi

You need to change the insertion region and simulation region precisely to accommodate the larger numbers of particle.

Happy learning !!

Thanks

laudari | Sun, 01/10/2021 - 00:43

Really thank you for your reply.
I am totally stuck here.
Could you please help me to get the insertion region?
How do you decide which coordinate is right while inserting particles?

Thank you