forked from lijiext/lammps
84 lines
1.9 KiB
Plaintext
84 lines
1.9 KiB
Plaintext
# sample LAMMPS input script for viscosity of 2d LJ liquid
|
|
# use shearing wall, thermostat via fix langevin
|
|
|
|
# settings
|
|
|
|
variable x equal 20
|
|
variable y equal 20
|
|
variable ylo equal -2.5
|
|
variable yhi equal 23
|
|
|
|
variable rho equal 0.6
|
|
variable t equal 1.0
|
|
variable rc equal 2.5
|
|
|
|
variable srate equal 2.7
|
|
|
|
# problem setup
|
|
|
|
units lj
|
|
dimension 2
|
|
atom_style atomic
|
|
neigh_modify delay 0 every 1
|
|
|
|
lattice sq2 ${rho}
|
|
region simbox block 0 $x ${ylo} ${yhi} -0.1 0.1
|
|
create_box 3 simbox
|
|
create_atoms 1 box
|
|
|
|
mass * 1.0
|
|
|
|
pair_style lj/cut ${rc}
|
|
pair_coeff * * 1 1
|
|
|
|
region lower block INF INF INF 0.0 INF INF
|
|
region upper block INF INF $y INF INF INF
|
|
group lower region lower
|
|
group upper region upper
|
|
set group lower type 2
|
|
set group upper type 3
|
|
group wall union lower upper
|
|
group flow subtract all wall
|
|
|
|
velocity flow create $t 97287
|
|
velocity upper set ${srate} 0.0 0.0 units box
|
|
|
|
compute thermal flow temp/partial 0 1 0
|
|
compute flow flow temp
|
|
|
|
fix 1 all nve
|
|
fix 2 flow langevin $t $t 0.1 498094
|
|
fix_modify 2 temp thermal
|
|
|
|
fix 3 wall setforce 0.0 0.0 0.0
|
|
fix 4 flow ave/spatial 20 500 10000 y center 0.05 vx &
|
|
units reduced file profile.wall.2d
|
|
fix 5 all enforce2d
|
|
|
|
# equilibration run
|
|
|
|
variable ybox equal $y*ylat
|
|
compute tilt flow temp/ramp vx 0 ${srate} y 0 ${ybox} units box
|
|
|
|
thermo 1000
|
|
thermo_style custom step temp c_tilt epair etotal press pxy
|
|
|
|
run 20000
|
|
|
|
# data gathering run
|
|
|
|
variable visc equal -pxy/(v_srate/ly)
|
|
fix vave all ave/time 1000 1 1000 v_visc ave running
|
|
|
|
thermo_style custom step temp pxy v_visc f_vave
|
|
thermo_modify temp tilt
|
|
|
|
# only need to run for 5000 steps to make a good 100-frame movie
|
|
|
|
#dump 1 all custom 50 dump.wall.2d id type x y z vx
|
|
|
|
#dump 2 all image 50 image.*.jpg vx type zoom 1.6 adiam 1.2
|
|
#dump_modify 2 pad 5 amap 0.0 ${srate} ca 0.0 2 min blue max red
|
|
|
|
run 50000
|