According to your last comment, in order to simulate a steady flow at a given velocity, I initialized the flow with a velocity command and added a small force, to compensate for the dissipation of energy through
interaction with the walls:
velocity flow set 1.0 0.0 0.0
fix 1 flow addforce 0.01 0.0 0.0
In order to define "temperature" for the flowing medium, I used "compute temp/com" command to exclude the kinetic energy of the center of mass of the flowing medium:
compute hot upper temp
compute flow argon temp/com
compute cold lower temp
Moreover, for controlling the temperature of the walls I have used the following commands:
fix hot upper nvt temp 150 150 0.01
fix cold lower nvt temp 90 90 0.01
fix nve flow nve
The temperature of the flow region decreased after I used the "compute temp/com" from 1250 to 840 but there are still some biases.
I would really appreciate if you could help me to figure it out.
On Wednesday, October 4, 2017 6:27 PM, Axel Kohlmeyer <akohlmey@...24...> wrote: