LIGGGHTS® - User Forum

I am trying to use a adforce command to apply a stoke's drag force on a single particle using the following syntax

atom_style granular
atom_modify map array
communicate single vel yes

boundary f f f
newton off
units si
#region reg sphere 0.1 0.1 0.1 0.4 side out
#region reg block -0.05 0.05 -0.05 0.05 0. 0.15 units box
#create_box 1 reg
region reg block -0.005 0.005 -0.005 0.005 0.000 0.002 units box

read_data velo

#processors 2 2 1

I am using compute like this

compute kash all property/atom z

compute kashi all property/atom x

compute kish all property/atom y

variable b equal c_kash[1]

variable p equal c_kashi[1] #r

And I am getting an error "Compute used in variable between runs is not current. Use the update_on_run_end option for computes to avoid this". I want to Know how and where to use the update_on_run_end option. in Variable command or in compute command above variable.

Hello All, I have a question on fix move rotate command in LIGGGHTS. Setup has a drum made up of particles, closely placed so that there is no gap.

I'm first using
fix wall particleWall freeze to freeze particles and then using
fix particleWallRotate particleWall move rotate 0.0 0.0 0.0 0.0 0.0 1.0 0.05 to rotate wall with a constant period of 0.05 sec.
This is working okay.

Hello,

Can anyone please show how to set liquidsource and liquidflux with washino/capillary/viscous, i looked everywhere but i found nothing.

any ideas ?

Regards.

I am using a If command (if "${b} <= ${bod1}" then "variable bod1 equal v_b") and getting an error (Compute used in variable between runs is not current. Use the update_on_run_end option for computes to avoid this.) I am trying to define update on run. when i try to do that they say illegal variable command. how and where to define update on run in variable defined in if command. I have defined variable like this (variable bod1 equal 1e-5) (variable b equal c_kash[1] ) (compute kash all property/atom z ). Can you please help me editing these commands to get rid of an error.

Hello everyone!! I am a new to liggghts and have installed and successfully running my simulation. The only issue is that liggghts uses 1 by 1 by 1 mpi grid set up even though I give command mpirun -np 8 .................
I am using Ubuntu 18.04 on a 12 logical core system. Someone please help.

Hello all,

I am running a shear test simulation and I would like to see some force chains. I use the command
" compute fc all pair/gran/local id pos force"
but because of that my simulation results change.

Hello

I m working on a research project and i want to dump f_surfaceLiquidContent[0] but it seems like it s giving me wrong values, im attaching my script and the results with you, so can someone please gives a help

Hi all,

i have a cylindrical shear cell geometry. In order to lower the computational cost i want to use periodic boundaries. I know that i can not unfortunately use "pie slices" (sorry if thats not the correct term) only boxes. The geometry has the be able to rotate also to simulate shearing.
Is there a way to simulate half of the shear cell with a cartesic periodic boundary approach? How can set this up? Are there any other possibilities to reduce computational time i can think of?

Thanks a lot this forums helps tremendously.
Kind regards

I want to ask about using different contact models for superquadric particles. I can see only the following contact models are available in the "style_contact_model.whitelist" file for superquadric particles:

GRAN_MODEL(HOOKE, TANGENTIAL_HISTORY, COHESION_OFF, ROLLING_OFF, SURFACE_SUPERQUADRIC)
GRAN_MODEL(HOOKE, TANGENTIAL_NO_HISTORY, COHESION_OFF, ROLLING_OFF, SURFACE_SUPERQUADRIC)
GRAN_MODEL(HOOKE, TANGENTIAL_NO_HISTORY, COHESION_OFF, ROLLING_CDT, SURFACE_SUPERQUADRIC)
GRAN_MODEL(HOOKE, TANGENTIAL_NO_HISTORY, COHESION_SJKR, ROLLING_OFF, SURFACE_SUPERQUADRIC)