LIGGGHTS® - User Forum

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

slow down my system

raguelmoon's picture
Submitted by raguelmoon on Wed, 12/08/2010 - 16:01

Hi,
I am pouring small particles in simulation box containing one big particle, during pouring I get this message many times:
INFO: more than 255 touching neighbor atoms found, growing contact history.

After a few timesteps my system slows down and stops working. Can anybody tell me about the problem?
Thanks,
Ram

Printout of # of particles

Submitted by cstoltz on Tue, 12/07/2010 - 20:08

I'm running a simulation in which a bin is initially filled with equal masses of two different particle types (identical properties except radius), and then opened at the bottom to allow the particles to pour out. Can anyone help me figure out how to get the code to print out the number of each particle type remaining (or equivalently, the mass) using the thermo command?

Rotating insertion stream

Submitted by cstoltz on Tue, 12/07/2010 - 19:32

Does anyone know of a convenient way to create a rotating pour stream? I have an application where I'd like to insert particles into a tank (roughly a cylinder along z-axis) as a fairly high speed stream coming from a nozzle (more or less a point source) inside the tank, but the nozzle rotates about the z-axis creating a ring-like spray pattern.

I'm aware of the gimbal demo simulation posted at this board, and in a pinch, that might work, but I'm afraid it might be difficult to get the right kind of dynamics coming out of the tube.

Thanks,
Chris

Wear prediction - follow up

Submitted by alexander.polson on Tue, 12/07/2010 - 10:36

Hi Everyone

(I wanted to post the information below (and some more pictures) as part of the original "Wear prediction" topic, but the option to attach files was not further available. That is the reason I start this topic as a follow-up. Is there a better way?)

Further to the previous postings on this topic:

I dont think the problem is in Paraview. I did the following:
* I ran the chute_wear input file (in.chute_wear) on v1.2.1-beta and on v1.2.2-beta
* I used the output file "dump99800.vtk" from both above versions of LIGGGHTS to make attached image files that:

restart2data

raguelmoon's picture
Submitted by raguelmoon on Tue, 12/07/2010 - 02:29

Hi,
Restart2data file in tools is not compatible with LIGGGHTS. It gives following error message:

eading restart file ...
WARNING Restart file version does not match restart2data version
restart2data version = 15 Jan 2010
ERROR: Invalid flag in force fields section of restart file 1747942004

I want to convert restart file into data file. Can anyone help me?

Thanks in advance...
Ram

Wear prediction

Submitted by alexander.polson on Mon, 12/06/2010 - 18:05

Hi Everyone

I dont know if this problem is a post-processing or a LIGGGHTS problem. I hope this is the right forum.

I ran the "chute_wear" example in (LIGGGHTS 1.2.1). During visualizing the results in Paraview, I get an error which looks like the wear prediction function does not work right.

I show in the attached 3x files a Paraview view of the model from above (at the same timestep for all 3x files):
- "wear.png"
- "shear.png"
- "pressure.png"

Looking at "wear.png", it appears that:

coefficient of friction for wall

Submitted by adabubu on Mon, 12/06/2010 - 16:23

Hi, Christoph,
I read some papers about Janssen's equation. I have noticed that the friction angle of wall is involved in this equation. i know there is a command to define coefficient of friction, e.g. ' fix all property/global coefficientFriction peratomtypepair 1 0.7 ' , but as i understand, this 'coefficientFriction' should be for particles, so, how could i define coefficient of friction for wall?

thanks,

adabubu

How can I use dump local ?

JF's picture
Submitted by JF on Mon, 12/06/2010 - 11:34

Hello Christoph,

I don't manage to use dump local, because I have some difficulties to understand the manual.

I compute some variables:
compute e-data all pair/gran/local history torque

For example, How can I dump the history :
dump dmp all local 2000 post/essay c_history

Please, can you help me by writting an example of dump local ?

Regards
JF

Pages

Subscribe to RSS - LIGGGHTS® - User Forum