[lammps-users] About units in ave/spatial for viscosity calculation

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1

Dear All,

I am trying to obtain the viscosity of liquid metallic alloys using RNEMD (Muller-Plathe method).

I have a doubt about using the “units” keyword in ave/spatial fix for recording the velocity profile.

As it is given in the doc page, “the units keyword determines the meaning of the distance units used for the layer thickness delta and for origin if it is a coordinate value…”.

In the original simulation box, the units are metal. While running the simulation for viscosity measurement, I set the the units keyword to be “reduced” in the fix ave/spatial. What I understand from the above sentence as given in the doc page is: this unit keywords is just related to the box dimension and not to the other quantities. Is it OK? From the results, I feel that it is alright. Still, I want someone to suggest if it is wrong.

Thanks,

Kirit Lad

2

The units option for fix ave/spatial only refers to
the origin and delta settings in that one command. If
you use box they will be Angstroms (since you are using
metal units), but if you use reduced, they will be 0-1.

Steve

3

Dear Steve

Thanks for the reply.

Kirit Lad