Filling a horizontal cylinder using "fix pour"

Submitted by alexander.polson on Mon, 06/07/2010 - 15:10

Hi Everyone

I want to make a drum with a horizontal center-line and "fix pour" spheres into it.

1) If I pick the Z-axis for this center line and gravity pointing to -Y, then I get:

"ERROR: Gravity must point in -z to use with fix pour in 3d"

2) OK, so I pick the X-axis for this center line and gravity pointing to -Z, then I get:

"ERROR: Must use a z-axis cylinder with fix pour"

So it seems the cylinder must be orientated with its center-line parallel to gravity, or am I missing something? The work-around is then to create the positions, then transform the coordinates, and read_data.

Any ideas, please?

Thank you

Alexander

Forums:

ckloss's picture

ckloss | Mon, 06/07/2010 - 15:14

Hi Alex,

gravity has to pint in -z direction. The insertion region for fix pour is either a z cylinder oder a block.
In your case, I would recommend a block as insertion region
The drum can be imported with fix mesh/gran from CAD (so that you can rotate etc.)

Christoph

chow2003 | Mon, 06/24/2019 - 14:39

hey,

I want create the particles in cylinder of 245 mm diameter and 74 mm of height ..but it is not creating particles at exact position. Please help me

Code below:::

soft_particles yes
units cgs
atom_style sphere
atom_modify map array sort 10000 2.0
neigh_modify delay 0 every 1 check yes page 500000 one 50000
boundary m m m
newton off
communicate single vel yes
processors * * *

# Domain
region reg block -1 1 -1 1 -1 1 units box
create_box 3 reg

### Setup

# Material and interaction properties required
fix m1 all property/global youngsModulus peratomtype 250 250 250
fix m2 all property/global poissonsRatio peratomtype 0.25 0.25 0.25
fix m3 all property/global coefficientRestitution peratomtypepair 3 1 0.5 1 0.5 1 1 1 1 1
fix m4 all property/global coefficientFriction peratomtypepair 3 1 0.5 1 0.5 1 1 1 1 1
fix m5 all property/global characteristicVelocity scalar 0.1

###Particle Insertion

region bc1 cylinder y 0 0 12.225 0.1 0.74 units box

alexander.polson | Mon, 06/14/2010 - 20:53

Hi Everyone

I am experimenting with the "fix pour" function in LIGGGHTS_1.0.3 and have this problem: the spheres are not generated where I am expecting them. The input below is intended to pour 1000 spheres into a cylinder on the z-axis, starting at z=0 and ending at z=0.3, with radius 0.7

The result is however a cloud of spheres that for a z-cylinder centered at (x,y) = (0.5,0.5) and starting at z=0, ending at z=1.

Can you see my mistake?

Thank you

Alexander

#------------ INPUT ---------------------
# Test the "pour" function to fill a drum with particles

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

# Set region for pouring particles: a cylinder with centerline
# on the z-axis. The cylinder starts at z=0 and stops at z=0.3,
# and has a radius of 0.7

region REG_drum cylinder z 0. 0. 0.7 0. 0.3 units box
create_box 1 REG_drum

group GRP_balls region REG_drum

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 0.7
fix m4 all property/global coefficientFriction peratomtypepair 1 0.05

pair_style gran/hertz/history 1 0
pair_coeff * *

fix 1 all nve/sphere
fix 2 all gravity 9.81 vector 0 0 -1

fix 3 GRP_balls pour 1000 1 999 &
region REG_drum &
diam uniform 0.012407 0.012407 &
dens uniform 1000 1000 vol 0.6 10

timestep 0.0001

dump 1 GRP_balls atom 1 test_atoms.*.txt

# See generated spheres in test_atoms.1.txt

run 1

ckloss's picture

ckloss | Mon, 06/14/2010 - 21:02

Hi Alex,

the code does what I expect...

>>the spheres are not generated where I am expecting them
I see particles generated in the cylinder, 1000 in total.

Can you explain where the problem is?

Best,
Christoph