LIGGGHTS® - User Forum

Hello LIGGGHTS forum,
I was trying to simulate a spherical particle motion in a flat rotating platform with an initial push given to the ball such that there is no slipping between ball and the rotating platform. Now according the several studies the balls angular velocity should be 2/7 of the rotating platform angular velocity with maintaining a stable circular orbit.
The simulation results were successfully maintaining a stable circular orbit but the ball angular velocity is quite higher than the reported value.

Hello LIGGGHTS forum, I am trying to run a simulation in an inclined surface. Till now my script is working nicely.
I want to add viscous and damp command in my script.

When ever I added it as ` fix 1 viscous 0.1 ` or `fix 1 damp viscous 0.5 scale 3 2.5` I got following message.
```
ERROR: Could not find fix group ID

```

I also tried to add as `fix m6 viscous...` got the same error.

How do I add them correctly?

Any help would be appreciated.

Thanks a lot.

My script

```

# Initialize

Hello everyone!

Hi all,

i want to install Liggghts on a redhat server and there are issues with the VTK part. The AUTOINSTALL_VTK flag is not working. I get the error: "Could not determine suitable appendix of VTK library with VTK = ... etc." when doing "make auto".

So i tried to manually install VTK. Configuration and Generation went without errors, altough i switched OFF everything besides mpi usage of VTK. After that i built VTK without error. But i do not find a folder usr/local/include. So i can not set the path in the Liggghts make file.

Hi all,

i want to model particle agglomerates that are hold together by Van der Waals force. For 1 agglomerate i read in the particle positions that form 1 agglomerate. What can i do to insert multiple particles of the same sort and size? Defining every particle position by hand is very tedious. I have 200K agglomerates in total. Multipsheres work nicely but they break ALL at once and i don't want this beaviour if i model the cohesion by Van der Waals force.

THANKS for any hints!

Hi all,

First thanks for the great resource, I have been working on this for hours before I decided to post here.

I have followed the steps of this post: https://www.cfdem.com/forums/installation-error

and think I have VTK installed and have gotten past several issues. Now when I select make auto it runs for a while which is encouraging, but gets stuck on the same errors from this post:

Hi, my name is Joaquin Gonzalez, currently im doing a job in LIGGGHTS.
Its about a test of wear in a mining dump truck, when im in the multisphere case, i recieve the follow error: Energy calculated for multisphere particles is currently not correct.
i will be so thankful if someone can helpme whit this.
I attach the input script and a picture of the screen with the error
Thank you

hello all,
I was going through the internal codes of Liggghts and found that tag and mask variables are set for each particle. can anybody kindly tell me what are those? As far I understood is the tag is the unique id for each particle and the mask is the processor number in which a particular particle's information is stored. kindly correct me if I am wrong.
thanks in advance.

Best,
Tarun

EDIT: issue has been solved, numerical inaccuracy on my part

SORRY

Total # of neighbors = 3481808
Ave neighs/atom = 17.4315
Neighbor list builds = 118828
Dangerous builds = 0
ERROR: Invalid dump style (/build/buildd/liggghts-3.0.3+repack/src/output.cpp:574)
dem@LIGGGHTS:~/Documents/litgg$

any one please help rectifying this error.