LIGGGHTS® - User Forum

Good morning,

Does anyone know which magnitude is used as the 'particle radius' for calculation of Rayleigh time-step of a multisphere representation?

Thank you in advance,

hi there,
I found out that there are 2 command that can give the heat flux of the particles:
1. fix heat/gran/conduction command
2. compute pair/gran/local command
And i guess the unit of both heat flux is energy/time (J/second). and i guess both of them are conductive heat transfer between particles.
So, what is the different between them?

P.S. i tried some cases, the output of these two command are different, although both of them named HeatFlux.
thx.

HI there,
I wonder if there is any example or tutorial to tell u how to calculate (or estimate) the effective thermal conductivity of a granular bed using LIGGGHTS?
thx

Hi,

I'm trying to find out contact between particles in huge size simulation which contain millions of particles.

What i'm using for this is

compute (name) (group name) pair/gran/local id pos force_normal delta

and then

dump (name) (group name) local (time step) (directory) & c_(name)[1] c_(name)[2], ... c_(name)[13]

But the problem caused here is when particle id is over 1 million, then particle id becomes 1.0e+06.

And it seems like ones place number is missing.

Is there a way to increase the precision in my dumped files? When I use the write_dump command, it only outputs data up to 6 significant figures. I have a simulation with over 1 million clumps, and I need to know the id's of each clump. So after the 1 millionth clump, the id number rounds to the nearest 10. I am dumping .txt files, so maybe there's a better file format I could use? Or is it a LIGGGHTS issue?

Hi All,

Is there a way to collect and dump the collision energy loss between different contact types in LIGGGHTS? I am simulating a grinding mill, and intend to calculate the energy loss between the particle and the CAD geometry after they collide

Thanks for your help.

Will

Hi
I am new user if LIGGGHTS and I am trying to do simulation but I am getting error. I am using the given error

fix cad1 all mesh/surface/stress file meshes/isgec1.stl type 1 scale 0.001 curvature 1e-05 wear finnie

Dear all,

Now, I have settled down all particles on the surface (large size distribution and shape distribution) and begin to start the simulation from the restart file.

I set the gravity as the Y direction and want to make particles only move in x-y plane. But I do not know how to let particles do not do any motion in z direction. It seems that fix/setforce does not work.

Are there any suggestions?

Looking forward to your kind help. Thank you very much in advance.

Best wishes,
Solient

With LIGGGHTS 3.8.0 the script below returns the error

"ERROR on proc 0: Random number generation: It is required that the random seed value is > 10000 and a prime number.
The random seed used was 38914"

What's happening? The random seed provided is not 38914, that's the number of particles! Is it a bug?

Hi there,
I was trying to run one of the LIGGGHTS examples: LIGGGHTS/Tutorials_public/ParScale/heatTransferBed_paScale/.
I installed the ParScale following the instructions and no error appears .
When i trying to run LIGGGHTS/Tutorials_public/ParScale/heatTransferBed_paScale/Allrun_convective, the following error apppears:

Total # of neighbors = 73
Ave neighs/atom = 0.09125
Neighbor list builds = 1
Dangerous builds = 0
ERROR: Invalid fix style: "couple/pascal" (../modify.cpp:850)
data2Plot = heat.json