LIGGGHTS® - User Forum

LIGGGHTS® related topics can be discussed here: discussion about models, installation, feature requests and general discussion

Using Ray Tracing to Model Thermal Radiation in LIGGGHTS

Submitted by apsantos on Tue, 11/01/2022 - 01:07

Hello LIGGGHTS community. I am new to LIGGGHTS, having mostly used LAMMPS.

I am interested in incorporating radiation in DEM models for some phenomena where it is likely a large heat transfer mechanism.

I saw a 2013 presentation and seminar paper by Stefan Amberger, Christoph Kloss and Stefan Pirker on "Using Ray Tracing to Model Thermal Radiation in LIGGGHTS".

Free moving meshes under the effects of particle interaction and gravity

Submitted by Mide2001 on Wed, 10/26/2022 - 00:48

Hi Guys,

I am new to LIGGGHTS and struggling to create a free-moving mesh. Basically, I'm trying to create a mesh that moves and rotates under the effect of particle interactions and gravity. Is there a way to do this in LIGGGHTS? Any help would be greatly appreciated.

Thanks

Formula for kinetic energy

Submitted by krobot on Thu, 10/20/2022 - 13:32

Hello People,

i am a newbie in the LIGGGHTS. I am trying to calculate kinetic energy of two movie particle of same material type. Two Particle has the diameters of 3 and 5 micrometer. I can't match the same value down there with hand calculation for KinEng.

Memory usage per processor = 1128.1 Mbytes
Step Atoms Volume KinEng
0 2 125001.5 0
1 2 125001.5 3979.3507
2 2 125001.5 3979.3507

How to determine convergence?

Submitted by hemezz on Tue, 10/18/2022 - 09:02

Hello all,

I am a student who is very new to using LIGGGHTS, but I'm building a simulation of packed particle flow over a surface to study abrasion of that surface. Since the surface is uneven, the flow of particles isn't always laminar, and in some regions the particles may flow faster than in others. I'm wondering if anyone can tell me how to determine when the simulation has reached convergence - in other words, how do I determine how many timesteps are "enough?"

Efficient Repetition of Commands via Loop-like structure

Submitted by apvyas on Wed, 10/05/2022 - 08:25

Hello!

I have a series of commands I would like to execute in an increasing fashion. For example:

1. [ Run 10 timesteps, set velocity of particles = 0 ] * 100
2. [ Run 100 timesteps, set velocity of particles = 0 ] * 100
3. [ Run 1000 timesteps, set velocity of particles = 0 ] * 100
4. [ Run 10000 timesteps, set velocity of particles = 0 ] * 100
etc.

Contact information for heat/gran/conduction

Submitted by Vasudha Kapre on Tue, 10/04/2022 - 17:14

Hello,

I have a LIGGGHTS model with a fix heat/gran/conduction. I want to output the conduction contact area information using the dump command. The following properties are mentioned in the online documentation - https://www.cfdem.com/media/DEM/docu/fix_heat_gran_conduction.html

Mix Control Mode of STL Wall

Submitted by shw218 on Thu, 09/29/2022 - 16:24

Hello Everyone,

I am modeling the soil-structure interaction, in which the structural material is represented by STL wall and is force controlled in x-direction and displacement controlled in y-direction. But I found once the STL wall is inserted as servo-wall, all directions of this mesh are force controlled. It seems like the mixed control (force and displacement) is not allowed to be exerted on one mesh in different directions. Is there any command I miss for this aim? Or do you have any suggestions for my problem?

Many thanks,

Shw

Maximum z-cooridnate(height) of pile in a region

Submitted by Skavya on Wed, 09/07/2022 - 10:54

Hi
I would like to find the Maximum z coordinate of particles pile in a region so i tried using
compute zMax all reduce/region region-Id max z
variable zmax equal c_zMax
print "Height of pile = ${zmax}"
i tried by placing run 0 also and giving compute id in thermo style and update_on_run_end also in compute id and how many times i tried it showing me same error
"compute in variable between runs is not current. try using update_on_run_end"
Can anyone help me with this problem
Regards,
Kavya

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