Particles cross the mesh wall

raguelmoon's picture
Submitted by raguelmoon on Tue, 07/13/2010 - 15:52

Hi LIGGGHTS users,
I have one simulation box and it is divided by mesh wall into two boxes. One box is filled with two types of particles and when I wiggle it using wiggle command the particles cross the mesh wall and come into the other box.
Please anybody can troubleshoot the error? Thanks in advance.
Best,
Ram

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ckloss's picture

ckloss | Tue, 07/13/2010 - 15:56

hi Ram,

are you using the most current version? There has been a change in LIGGGHTS 1.1.5 that might be related to that.

Also, it might be that the time-step is too high so that mesh change is so rapid that particles are instantaniously in the other box, check if v_wall*dt<0.01*dp, where dp is the smallest particle diameter

One more comment: Are you using 2 wall layers or just one? Because if you are using only one layer, particles may overlap the wall from both sides so they can still interact with each other

Best,
Christoph

ckloss's picture

ckloss | Tue, 07/13/2010 - 19:41

Hi Ram,

I am sure changing to 1.1.5 will resolve the issue - but it might also be a time-step issue, as mentioned above.
I would also suggest using a 2 layer wall so that it is guaranteed that the particles from 2 sides can not interact with each other

best,
Christoph

raguelmoon's picture

raguelmoon | Thu, 07/15/2010 - 16:50

Hi Christoph,
Problem still bugs me. I am using new version with 2 layers wall. Same problem occurs when I move base (from CAD mesh) in silo. The base moves downward but particles do not move, they stand where they were when poured. However, particles should also drag down with the motion of base as there is gravity along z-axis.

Best,
Ram

Ram