LIGGGHTS® - User Forum

Hello,
I am trying to simulate granular flow around a horizontal tubes of a particle heat exchanger and validate the results with the experimental results of Bartsch et at(https://www.sciencedirect.com/science/article/pii/S0038092X19300982) but I am getting zigzag velocity profile at any z plane but in their results they are getting a nice velocity profile. If anyone can help me regarding this problem then it will be thankful to you.

Hi,

I am attempting to compile LIGGGHTS on Ubuntu 20.04.

My Makefile.user has the following flags and paths set:

Created orthogonal box = (-0.4 -0.05 -0.05) to (0.35 0.1 0.4)
2 by 1 by 2 MPI processor grid
ERROR on proc 0: Cannot open mesh file mesh/Box.stl (../input_mesh_tri.cpp:115)
--------------------------------------------------------------------------
MPI_ABORT was invoked on rank 0 in communicator MPI_COMM_WORLD
with errorcode 1.

Hello,
I am the beginner in LIGGGHTS and I am trying to get the particle distribution/ volume fraction of any local region of the DEM simulation domain. I came to know in the forum that it can be done by Voro++ but I don't have any idea how to use it. Can anybody help me in this regard? It will be really great help if anyone can do.

error:

Primary job terminated normally, but 1 process returned
a non-zero exit code. Per user-direction, the job has been aborted.
mpirun detected that one or more processes exited with non-zero status, thus causing
the job to be terminated. The first process to do so was:

Process name: [[5963,1],4]
Exit code: 1

In my understanding, liggghts use domain-based decomposition for parallelizing. In my case, some of the same set of elements are processed by different processors. Please suggest some way to avoid that.

Dear LIGGGHTS users,

I'm wondering how can I fix the walls in the simulation to prevent their movement (not from the beginning, at the certain point of my analysis).

Thank you!
Bee

Hi everyone,

I'm working on a DEM simulation of TRIAXIAL COMPRESSION TEST (Lateral wall under constant pressure, fixed bottom, and strain(velocity) controlled loading at the top) on a cylindrical shaped assembly of particles recently. Some questions bothered me so I'd like to ask for suggestions on how to implement the requirements using existing commands without programming.

Hello
I am currently using Liggghts-flexible fibers. In the bond_gran.cpp file, it calculates the total bond energy using elastic assumptions, and use set bond energy later on.
Actually I am modifying the bond gran.cpp file to include the nonlinear material model, and the formulation with elasic assumptions will not be valid anymore. However I don't need bond energy as an output on my simulation.
I just wanted to clarify, will it affect the simulation accuracy/performance if I keep the bondenergy part erroneous?

Thanks
Shubham

I got two kinds of particles in the .liggghts output. I used 'lpp' and opened in Paraview, but it displayed in the same size.
I tried 3D Glyphs filter with the 'scaling' option. The particles size changed but they are still in the same size.

Hi,
I need to fix the position of some multisphere particles at a specific position in the simulation domain before starting a CFD-DEM simulation. I am having a hard time finding the right command or approach to do this. Is there any way to fix the position of each multisphere particle in the simulation?
Something like the "set" command for single particles in the "twoSphereGlowinskiMPI" tutorial files:
...
atom_type granular
....
# create single partciles
create_atoms 1 single 1.2 0.5 0.5 units box