LIGGGHTS® - User Forum

Dear LIGGGHTS/CFDEM developers,

I am interested in modelling fluid-clusters interaction using the LIGGGHTS-OpenFOAM coupling scheme. However, I am facing a problem on the calculation of drag force on clusters (or non-sphere particle).

The cluster is composed of large number of spheres, since drag force is Surface Force, that means there is no drag force acting on the internal particles within the cluster. but the default CFDEM solver will calculate drag force on every particle, hence the Resulting drag force on the Cluster is much bigger.

Is it to simulate the particles in LIGGGHTS with two Young modules, e.g., the soft external part and the hard internal part?

Hej guys,

does anyone know which parameter cause the madness of one particle which kicks all the others out of the world?
This problem appears when i scale down the radius of the particles.

this is my input script:

>>>
units si
newton off
boundary f f f

atom_style granular
atom_modify map array

region world block -10 10 -10 10 -10 10 units box
create_box 1 world

neighbor 0.001 bin
neigh_modify delay 0

communicate single vel yes

Hello,

Hi all,

I like to insert continuously multispheres particles into my LIGGGHTS run by defining is as a molecule, but I saw that the commands used by LAMMPS to do so are not the same in LIGGGHTS, so, I was asking myself, if I want the same command as LAMMPS, could it be enough to take the function in LAMMPS and then just change the function in LIGGGHTS (for example for fix pour)? if not how should I do?

Thanks all

Hi everyone,

I'm trying to pour a certain number of particles over different bodies and shapes.

The problem is that when I visualize the results of the simulation in paraview I don't know how paraview sets the origin of coordinates for the .stl body.

I was also trying to figure out where the .stl body is located when I run the simulation in liggghts? Is there a default position?

Thank you for your attention,
Jonathan.

Hi,

I have been working on a project regarding compressing and tensile of a solid material.

I had not any problem in compressing part and I utilize "fix X1 all mesh/surface/stress/servo" to do that and the results is perfect.
My problem is in tensile part. When I utilize the previous commend for tensile in one direction, there is no tensile is observed. I implement "Fix move/mesh" for tensile in that direction, but I could not observe any tensile.

I want to know if it is possible to model tensile using LIGGGHTS.

Hi everybody,

i am trying to parallelize the LIGGGHTS calculation, but it seems that it doesn't work with "mpirun -np 8 liggghts in.script"
In the "in.script" i placed the command "Processors 2 4 1" to divide domain into subdomains.

The error i got is:

Hi everybody,

I met some problems on displaying particle in paraview. In my modeling, I have two types of particles. When I postprocess the vtk data in paraview. In 'Coloring' category, I choose 'type'. But the two type particles display the same color. I check the vtk file and there are two types there. Can anyone help to explain why? Besides, how can display particle in real size? Thanks.

See picture below.
The left port is fed with type 1 particle and the right port is fed with type 2 particle

Hi,
I am trying to perform a simulation with the pair style "hybrid/overlay" combining "hertz/stiffness" with "lj/cut" (see attached script)
However, the simulation crashes as soon as a particle touches a wall (this happens at timestep ~9400 in my simulation).
Does anybody have an idea what I am doing wrong in the script?
Note: The simulation runs fine if one removes the walls!
Thanks in advance!
Best
Eric