I have a question about pair_style. I'd like to simulate solid materials such as shale, clay, sand, and like this. I need to know what the appropriate pair_style for doing that is?
Another question is about integration. In my project I have to decrease temperature from X1 to X2. How can I do that?
And using "fix integer nvt/sphere temp X1 X2 DX" is true or not?
Thanks a lot for the response in advance.
moritzhoefert | Tue, 08/27/2013 - 13:05
Hi rasoul,
Hi rasoul,
NVT ensembles are usually used for molecular dynamics and I think it does not make sense to use that for DEM simulations. In MD temperature is a directly accessible quantity: the velocity fluctuations of atoms. And the thermostat is applied to those. In DEM temperature is a per particle quantity independent of the velocities.
You could use fix nve/sphere to propagate the trajectories of DEM particles and heat/gran/conduction to track temperature.
Best,
Moritz
rasoul | Tue, 08/27/2013 - 22:47
nvt or nve
Thanks a lot for the response. So, how can I fix temperature in a target point or decrease it slowly?
ckloss | Fri, 08/30/2013 - 15:15
Hi rasoul,
Hi rasoul,
as Moritz said, NVT is for molecular dynamics, and temperature here is temperature in the sense of kinetic gas theory, which is not approropriate in this case
have a look at the heat transfer tutorials that come with LIGGGHTS.
with the "set" command, you can set the temperature of particles as you desire
Cheers
Christoph