[gmx-users] Velocity as a function of distance Z

[Kamps, M.]

Dear gmx-users,

I have several simulations regarding atoms flowing between two gold
surfaces. The flow of the liquid molecules show a distinct Poiseuille
flow, which was expected.
I am now interested in extracting the velocities of these liquid
molecules (total of around 30000 atoms, around 700 molecules).

I am interested in the (average) velocity, as a function of the height
Z. Is this possible in any way?

If I take for example the command gmx traj ... -av, I will get the
average velocity of all atoms, however I cannot tell which atom is
placed where. Furthermore, is it possible to get the average
velocities per molecule instead of atoms, for instance via gmx traj?

Thanks in advance.

Mark