Couette Flow Slip vs. No Slip

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1

Hello,

I recently downloaded the LAMMPS input script for Couette flow and am having trouble figuring out how to make the flow with slip and no slip boundary conditions. Is there a way to ensure that the velocity of the atoms at the wall equals the velocity of the wall? I am also looking to make slip conditions so that the velocity of the atoms at the wall is slightly less than the velocity of the wall.

What method can be used to achieve these results? I know that by increasing temperature, the atoms will move much faster than the wall and that by decreasing temperature, the atoms will move slower, but I think there must be another way.

Any help would be much appreciated.

Thank you,

Ben

2

Why are you trying to apply coarse-grained boundary conditions(fluid dynamics) to a molecular system? You should have some theoretical basis for slip conditions to exist. Solving the inverse problem, (finding the micro-scopic conditions that lead to observed macro-scopic behavior), is probably not a particularly fruitful direction to go. You might start with conditions more specific to an actual system.

Also, thermal energy is fluctuational, what has that got to do with atoms moving faster than the wall, there is zero net motion. All changing the temperature does is modify the Mach number.