LIGGGHTS® - User Forum

I have two cad files in my simulation. The one is auxiliary just works as splitter and need not to be visible in final results. I know I am using line "dump dumpstl all mesh/stl 200 post/dump*.stl" in my script which applies to all meshes, and by changing the group-ID the issue can be handled. But I don't know how to assign group-ID to stl files (or mesh groups).

Anyone please help...
An example would be really appreciable.

Thanks in advance.

Hi all,

I have a general question for the LIGGGHTS user who are experts on DEM and also on CFD or SPH or Lattice Boltzmann.

I want to model the behaviour of a liquid (water or oil) between 2 surfaces constituted by DEM particles (i.e., spheres). So as to obtain the pressure and the friction induced by the liquid properties within the contact on the DEM surfaces.

I don't know which fluid method I can use with DEM part of LIGGGHTS to perform this simulation because I don't know SPH and CFD very well.

For using "fix mesh/surface/stress/servo" I have to implement mesh (file filename.stl).
How can I do that?
I do not input mesh in my simulation.
Is there any other ways?

Thanks a lot in advance,

Dear all,

I am going to track particles in my fluidised bed simulation. For instance , 1000 particles are inserted into the domain and I am going to track particles with the ID between 200 to 500.

Does anyone have an idea about how I can track particles based on their ID in LIGGHTS.

Best regards,
Ebrahim

Hi,
I am running a simple case of particles tumbling in a rotating drum using LIGGGHTS v2.3.7 and observed tiny explosions. I have run this case before using an earlier version of LIGGGHTS (v2.1.2 ) and did not see any such explosions. I am not sure what changed between the version to suddenly cause these explosions.

I have a query that may appear peculiar. Actually, I have installed either LIGGGHTS 2.3.6 and LIGGGHTS 2.3.7 in 3 of our laptops and one workstation with Ubuntu platform (both 12.04 LTS and 13.04). All were working fine earlier. But now when I cd to .../examples/LIGGGHTS/Tut../example in a terminal, and run liggghts > in.script then nothing happens in terminal.
Moreover, the code inside the relevant in.script get deleted or sometimes replaced by this message "LIGGGHTS (Version LIGGGHTS-PUBLIC 2.3.6, compiled 2013-09-06-14:07:53 by root based on LAMMPS 20 Apr 2012)".

Hi all,
I am new to LIGGGHTS and to the LINUX OS. I have been following the installation tutorial for fedora. When I follow this part of the tutorial:
+ in the /src directory, type "make clean-all", then "make fedora"
I get:

Hi Chris,

I tried to reconstruct the CFD results of "twoSpheresGlowinskiMPI" case, however it seems not possible right now, due to the refined mesh generated during the run.

So i thought run the case with only 1 core will solve this issue, but with dataExchangeModel twoWayMPI the solver does not allow running on single core, even I changed the

mpirun -np $nrProcs $debugMode $solverName -parallel 2>&1 | tee -a $logpath/$logfileName

to

$solverName > $logpath/$logfileName

I need to know is there any command or tactic/solution for adding stress (psi) to the one surface/edge of a simulation domain (box) which is poured by particles?
I have attached a picture that can help you to understand me.

Thank you for your help in advance,

Sincerely,
Rasoul

Hello,
I want to simulate the flow of lubrication oil in bearings using the SPH-Method.

So I need an inner and outer ring that rotate around the origin(0,0,0) in opposite direction and several rolling elements that rotate around their own axis. And at the same time I need a rotation gravity vector, that rotates with the same angular velocity as the outer ring, using the gravity gradient command.