# How to control temperature when one boundary is moving

Hello everyone,
I am trying to simulate a system where the bottom wall is fixed and the top wall is moving ( z direction ) towards the bottom wall.

So I used fix move
But I see the temperature is very high ~200000, how do I control the temp ?

I used temp modify and temp/rescale.
Probably I am not putting it in the right way.
Can anyone suggest me something on how to keep the temperature at 300 K ?

Mani

Here is my input script:

clear
units real
boundary p p s

#Defining the different potential types
pair_style lj/cut/coul/cut 12 12
atom_style full
angle_style harmonic
bond_style harmonic
dihedral_style harmonic
improper_style cvff

neighbor 2.0 bin
neigh_modify delay 0 every 1 check yes
neigh_modify every 1 delay 0 check yes one 200000 page 2000000
pair_modify shift yes mix arithmetic

group fluid molecule <> 2 13
group base1 id <> 1 10368
group base2 id <> 20737 25344
group top1 id <> 10369 20736
group top2 id <> 25345 28800
group base union base1 base2
group top union top1 top2
region 1 block -INF INF -INF INF 0.0 10.0 units box
group boundary region 1

fix freeze1 top setforce 0.0 0.0 0.0
fix freeze2 base setforce 0.0 0.0 0.0

#Setting MD

#fix 1 all nvt temp 300 300 50.0
compute mobile all temp
velocity fluid create 300.0 482748 temp mobile
#fix 1 all nve
fix 9 boundary move linear 0.0 0.0 0.5 units box
fix 11 all temp/rescale 100 300.0 300.0 50.0 0.5
fix_modify 11 temp mobile

timestep 0.1
thermo 100
log log_tempAB
dump 3 all xyz 1000 dump.AB.xyz
run 10000

I am trying to simulate a system where the bottom wall is fixed and the top wall is moving ( z direction ) towards the bottom wall.
So I used fix move
But I see the temperature is very high ~200000, how do I control the temp ?

That indicates you are moving the wall far too fast and too far.
You can't control the temp when you are doing crazy things
to the system.

Steve