output velocity of a group of particles

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1

Deas Lammps users,

I am trying to simulate a liquid flow between two parallel solid walls. I have created 20 different groups for the flow region in the y direction (normal to the flow direction). How can I output the time-averaged velocity of each group?

Many thanks in advance for any help,
Santiago

2

I think using compute/chunk and fix ave/chunk will be much more handy than 20 groups for this purpose…

3

Thank you for your reply!

I think using compute/chunk and fix ave/chunk will be much more handy than 20 groups for this purpose…

4

If I use “compute chunk/atom” + “compute vcm/chunk” + “fix ave/time”, is that right?

I think using compute/chunk and fix ave/chunk will be much more handy than 20 groups for this purpose…

5

That depends on whether you want the time-averaged velocity of the center of mass or not.

6

Thanks again!

That depends on whether you want the time-averaged velocity of the center of mass or not.