[lammps-users] temperature compute lammps

actually I have a nanochannel of single layer graphene with fix nvt 300. after the system reached equilibrium the force on water applied along X-Axis. after that, I used compute temp/partial 0 1 1 to remove x-direction velocity bias and fix_modify to use that compute for thermostat the system in 300K but in this simulation the temperature along Y and Z is fixed too 300 but total temperature computed from thermo style command is very large with order of 70,000K and water velocity is 0.1 A/fs wich is too large.
but when I use fix nvt 300 after adding force and compute temp, everything is fine.

This sounds like you are adding too large a force, but also that you have not thought through what your model is and what your observations should be.

The temperature from the thermo output is using compute temp. So the difference between compute temp/partial and compute temp is caused by the additional force.

Please also keep in mind that when adding a force to a group you will accelerate that group until the added force is compensated by the friction or resistance the group experiences. Graphene is quite “slippery”, so the system can accelerate to a rather high velocity.

When using the default compute temp with fix nvt, the thermostat will remove the kinetic energy added to the system by the added force.