LIGGGHTS® - User Forum

Hello.

I am trying to simulate granular flow using LIGGGHTS.

In my simulated scenario, almost all particles are concentrated in the lower right corner of the boundary region, so the load would be not balanced if we simply divided the domain equally. Therefore, we need to modify the divided domain according to the distribution of the particles, e.g., allocating more worker processes in the lower right corner.

Greetings, i recently finished a simulation in LIGGGHTS 3.6, but when i try to post processing the information using "lpp", the process freezes. I use the cpunum command in order to reduce the cpu cores, but it still freezes and no error message is shown. I'm still waiting for restarting of the process, but it has passed more than 7 hours and nothing happen.

I add the lines from my console.

Hello to everyone

Is there a way to work with cuda processors to run a simulation in LIGGGHTS?. I have a Nvidia Geforce GTX 960.

Best regards.

Nicolás.

Dear liggghts users,

I want to set up a simulation with bonds (I am using liggghts-with-bonds) that has atoms with different sizes. I was not able to get different atoms with the „create_atoms“ command.

My idea was to first insert the atoms with the fix insert/pack command, let them settle and then create the bonds in order to have bonds and different sized atoms.

Hi there

Is it possible to calculate the force acting on the mesh/surface?

In my simulation, I use the fix top all mesh/surface/stress/servo file bottom.stl type 1 scale 0.03 move -0.015 -0.015 0.1 com 0. 0. 0. ctrlPV force axis 0. 0. -1. target_val 0.0003467 vel_max 5e3 mode auto ratio 0.01 to cap the particles. how can I manage to know the force on the mesh? because I suppose this command will set the wall compress the particles by 0.0003467N.

Thanks
Weijing

Hi,
i m working on mult-isphere particles mixing in cylinder . problem with my simulation is that some of the particles remain suspended during insertion and stick with impeller rod. if there is anyone who can help me out. i m uploading a picture of my problem. please help me.

thanx

Hello,

I am new to LIGGGHTS, so I tried to modify a tutorial example for a granular flow to create a 2D Couette flow. This is the example I am modifying:

https://www.cfdem.com/media/DEM/docu/Section_input_script.html#an-exampl...

I have got so far with the modifications, but I hit a problem. When I try and convert the dimension to 2D using this line:

dimension 2

The error message appears:

I'm trying to investigate how the different rolling friction models in LIGGGHTS effect my simulations. My initial simulation used the cdt model for the particles and walls, and I wrote restart files to prevent me from having to run multiple simulations from the very beginning.

However, when I change the rolling_friction model on the wall/gran fixes, I get an error:

ERROR: Fix contacthistory/mesh (id tracker_mesh1): saved simulation state used different contact history model - can not restart (../fix_contact_history.cpp:528)

Hi,

I wondered if there exists a way of coupling a solid model created in OpenFOAM, which solves the wave equation to a DEM model created in LIGGGHTS? The physical situation is a pipe filled with powder and the solid pipe is vibrated to fluidize the powder. The particle phase is dry (no effect of interstitial fluid) but the powder is affected by the vibrations of the solid model through the motion of the boundary, which changes throughout the solid part and depends on the frequency of vibration.

Kind regards,

Andrew

Can I compile liggghts on a Windows-7 ?
Can somebody provide the procedure for the same?

Thanks,
GAJ