Moving a mesh across periodic boundaries

Submitted by nitinkhola4491 on Fri, 10/25/2013 - 01:28

Consider a situation in which particles have been packed between two plates and say one of the plate is being moved. The boundary conditions are periodic in the direction of movement of the plate (the plate, an imported stl, is being moved in x direction using a linear style in fix move/mesh and the boundary conditions are periodic in this dimension, but it takes the plate out of the simulation box). Is there any command in liggghts which can help. If not is there any other way to implement it in liggghts ? Please suggest, I am a new user.

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ckloss | Thu, 10/31/2013 - 12:26

Hi nitinkhola4491,

wrapping meshes around PBCs is not implemented at the moment (this would involve some tricky details to be implemented).
However, if the dimension of the plate is equal to the box bounds, you can just add a surface velocity to the plate, this will do the same thing

Cheers
Christoph

nitinkhola4491 | Wed, 11/06/2013 - 22:33

Thanks Christoph,

It's okay about the mesh.

I am facing a new problem. I want to move a region with a group of rigid atoms(moving randomly in one dimension, not moving in other dimensions) such that the region always remains at a certain distance (in that one dimension) from the rigid group. I have been trying to use the region command with the move keyword. And in for the displacement variable I am trying to use the group function vcm (of the rigid group of atoms). But, as it works out, things are not going as expected.

I think that region can only be moved according to a 'predetermined' function of time and not according a group function. Am I right ? Or is it a way there which can help me move the region (only in one dimension) according to the movement of a rigid body in the simulation which is moving randomly ? Please help!!!