Particle Penetrate through mesh

Submitted by Subin on Fri, 11/03/2017 - 20:24

Hi,

I am new user of Liggghts and trying to simulation particles in micro units. However, when I insert particle, the fix wall/gran command does not work and the region keeps on increasing with the particle movement.

Can somebody tell me how to overcome this problem?

Thanks,
Subin

Forums:

paul | Fri, 11/03/2017 - 21:58

Is delta t << particle radius / particle velocity true? otherwise particles can pass through walls without resolving the contact properly.

Is the STL mesh in micro or si units? If unsure, have liggghts dump the mesh together with the particles and have a look what liggghts perceives.

Greetings,
Paul

Zheng Hu | Fri, 11/03/2017 - 23:02

Dear Paul, I am facing a problem about particles/wall interaction. In my simulation, I set two groups of particles and set the interaction between the wall and one group of the particles. In fact, I want to keep one group of particles passing through the wall while the other group prevented by the wall. Do you know how to make this? I have also attached a simple example in https://www.cfdem.com/forums/how-exclude-interaction-stl-mesh-wall-selec.... Could you please help to check where is the problem? Many thanks.

Subin | Tue, 11/14/2017 - 22:21

Thank you Paul!

One more question, when doing simulation in micro units, what is the unit of time-step size? Is is micro-seconds or still seconds?

Regards,
Subin