SINGLE PARTICLE

Submitted by govind on Thu, 08/10/2017 - 14:00

I want to generate single particle with large radius like a tennis ball. I am trying with given command of particle distribution but not getting success.
Actually I have task to impact a large size particle into the pool of smaller particles (big particle size is more than 20mm and smaller particles have size around 2mm).

Is this okay if instead single particle I use cad stl file of sphere? I tried this also but as stl(sphere) falls domain boundary stretches , I can not use fixed boundary as in this case particles get lost.

Please tell me how do I proceed?

Govind

Forums:

medvedeg | Thu, 08/10/2017 - 17:31

Hallo govind,

which problems are you facing? Please share input script file, logs, error messages, etc. It should be possible to use particles of different sizes, even with 10 times difference. You can define two particle templates with constant radius 1mm and another with 10mm. The combine them in "fix particledistribution". Uniform and gaussian size distributions are no longer supported.

Sphere as STL object is only possible if it is static or moving with predefined velocity. The functionality you are asking (with 6 degrees of freedom, https://www.cfdem.com/rigid-body-dynamics-6-degrees-freedom right?) is a feature of LIGGGHTS-PREMIUM.

Alexander Podlozhnyuk

govind | Thu, 08/17/2017 - 12:18

1. With "create_atoms" command I generate single particle of 20mm radius and with "fix particletemplate/sphere" I generate around 500000 particles of 2mm radius. I want single particle of 20mm radius to look like a tennis ball (large sphere).

2. As you say about sphere as STL and the link you have given for rigid-body dynamics , instead of cubic I want to use sphere. I am approachable to only public version of LIGGGHTS. I have to simulate spherical body impact into granular media that's why I am about to generate single particle.

Govind

govind | Tue, 08/22/2017 - 06:50

I got it from previous discussions. Thanks a lot to the user forum.

Govind