LIGGGHTS® - User Forum

Dear Friends,

Currently I have started to use pair_style gran/hertz/history/stiffness model in my DEM simulation.
In the LIGGGHTS manual I find that the specified parameters are multiplied by some other parameters like: the effective mass and radius, sqrt (delta n) .

I took a look on the source code and copy/paste them here:

double polyhertz = sqrt(ri*rj/(ri+rj)*deltan);

kn = polyhertz*k_n[itype][jtype];
kt = polyhertz*k_t[itype][jtype];
gamman = polyhertz*meff*gamma_n[itype][jtype];
gammat = polyhertz*meff*gamma_t[itype][jtype];

I am looking for an exmaple of cold spray or a similar sample. It also
appreciates that you can give some advice. I am beginner on Liggghts but there is very
interesting to know it.

Thanks in advance.

Simon

How can I implement "mesh/surface/stress/servo" using primitive walls?
I say this because in the "mesh/surface/stress/servo" command, we have to use "File Filename.stl", but I do not have any .stl file in my simulation and I control the simulation domain by primitive walls.

I am looking forward to hearing from you.

Regards,
Rasoul

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: