Dear all,
I want to modify the couette flow input code. I need to specify a low temperature (T=1) for the lower wall and a high temperature (T=2) for the upper wall and find the temperature distribution in the middle flow area.
The problem is the results are not reasonable since the temperature of the lower wall is "0" in the output file. Could any body help me figure out where the bugs are?
Thank you so much in advance.
Best,
Santiago
My modified code is as follows:
# 2-d LJ flow simulation
units lj
dimension 2
boundary p p p
atom_style atomic
neighbor 0.3 bin
neigh_modify delay 5
# create geometry
lattice hex 0.7
region mybox block 0 20 0 10 -0.25 0.25
create_box 3 mybox
create_atoms 1 box
mass 1 1.0
mass 2 1.0
mass 3 1.0
# LJ potentials
pair_style lj/cut 1.12246
pair_coeff * * 1.0 1.0 1.12246
##########
velocity all create 1.0 23652 mom yes rot yes
fix npt all npt temp 1 1 0.01 iso 0 0 0.1
##########
# define groups
##########
unfix npt
##########
region 1 block INF INF INF 1.25 INF INF
group lower region 1
region 2 block INF INF 8.75 INF INF INF
group upper region 2
group boundary union lower upper
group flow subtract all boundary
set group lower type 2
set group upper type 3
# Couette flow
velocity lower set 0.0 0.0 0.0
velocity upper set 3.0 0.0 0.0
fix 1 boundary setforce 0.0 0.0 0.0
fix 2 all enforce2d
########## HOT & COLD
fix 3 lower nvt temp 1 1 0.01
fix 4 upper nvt temp 2 2 0.01
fix 5 flow nve
##########
compute hot upper temp
compute middle flow temp
compute cold lower temp
##########
fix 6 all ave/time 1 10000 10000 c_hot c_middle c_cold file temp.txt
# Run
timestep 0.003
thermo 500
dump 1 all xyz 100 dump.xyz
dump 2 all movie 100 movie.mpg type type &
zoom 1.6 adiam 1.2
run 50000