LIGGGHTS® - User Forum

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

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:

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

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:

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

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

Hi,
How can I measure the packing fraction of static piling in cylinder?
Thanks in advance..

R

Hi, all

The input files for liggghts of an undrained triaxial test have been attached. Someone has sent me e-mail for this request. Actually, there is no inconvenience for me and I am pleased to share this.

I am a beginner and this example is not that good(you could see its q-p result in the ods file attached). This may be due to the velocity of compression is too fast or I did not use general equation to calculate q and p. If there are any problems you find or any improvement you give, please tell me cause I also need your help. Thanks for that.

Hi all,
Is there any way to set a parameter in LIGGGHTS to account for rolling resistance?
Thank you in advance,
Regards
Carlos

Hi, everyone, i'm new here. I used LIGGGHTS to simulate pouring problem. The balls are poured into a cylinder under gravity. After the calculation, i got the pressure on the bottom of wall. I would like to know this relationship between this pressure and the weight of balls. Based on soil mechanics, i know the pressure on the bottom wall should be equal the the weight of balls divided by the bottom area (Here i need to mention i am not familar with particle mechanics). Anyone can help me?