Problem with fix/wall/gran .... wiggle

Dear LAMMPS users,

I am trying to simulate 2D granular bed with the wiggle command on y-plane (bottom and top wall both) with the dimension of motion perpendicular to the wall (shaking of the bed).
I was expecting both the walls to move sinusoidally, but it is not (there is no change in the position of the wall). And with the momentum exchange of wall-particle interaction, particles will move.

I have attached both the input file as well the dump file for the reference: -

Thanks in advance !

Alok Tiwari
PhD Scholar
IIT Bombay, Mumbai

run69.txt (1.26 KB)

dump.txt (545 KB)

there is a change in the position of the wall, but you cannot see it because

  1. there is nothing in your input that will pull the particles toward the wall(s), so once they are pushed back, they will stay away and you won’t see the impact of the wall at all

  2. your ouput frequency is a multiple of the wiggle frequency, so every time you dump the wall is in the same location.