I am using LAMMPS to simulate a 3D couette flow, however, I could not
get the classic linear velocity profile. I created my script mostly
from the 2D couette flow example.
I created 2 slabs of wall atoms of type 1 and 3, flow atoms are of
type 2. For the wall atoms I use setforce 0 0 0 and gave the upper
wall atoms a constant velocity ux=1.0. Then I used fix ave/spatial to
get the averaged atoms number density and velocity profile. I tried
nvt,temp/rescale, langevin, but the results are same.
The results are very strange for both the number density and ux which
are attached with the script.
Your advice is greatly appreciated. The version i used is lammps-7Mar07.
In.flow.couette: the input script.
Ux.jpg: the velocity profile for ux.
in.flow.couette (1.42 KB)