poiseuille flow

im karthik. im new to lammps. im trying to get the velocity profile of a simple poiseuille flow in order to understand how lammps works. however i’m not able to get it from the example given in lammps. im not sure if the example is right as the visualisation of the same using vmd has not yielded satisfactory result. can you please help me to get the parabolic velocity profile. i do not understand as to why fix aveforce 0.0 -1.0 0.0 has been used?

Karthik N S
VI Sem (B.Tech)
Dept of Mechanical Engg

You can use fix ave/spatial to compute a velocity profile.
The fix aveforce command is pushing down on the top
wall of atoms to keep the system compressed with
an external force.


thanks a lot steve for replying so soon… will try it right away.