forked from lijiext/lammps
87 lines
1.9 KiB
Plaintext
87 lines
1.9 KiB
Plaintext
# sample LAMMPS input script for viscosity of 2d LJ liquid
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# NEMD via fix deform and fix nvt/sllod
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# settings
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variable x equal 20
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variable y equal 20
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variable rho equal 0.6
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variable t equal 1.0
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variable rc equal 2.5
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variable srate equal 2.7 # velocity of top edge
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# problem setup
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units lj
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dimension 2
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atom_style atomic
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neigh_modify delay 0 every 1
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# problem setup
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lattice sq2 ${rho}
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region simbox prism 0 $x 0 $y -0.1 0.1 0.0 0.0 0.0
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create_box 1 simbox
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create_atoms 1 box
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pair_style lj/cut ${rc}
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pair_coeff * * 1 1
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mass * 1.0
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velocity all create $t 97287
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fix 1 all nve
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fix 2 all langevin $t $t 0.1 498094
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fix 3 all enforce2d
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# equilibration run
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thermo 1000
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run 5000
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unfix 1
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unfix 2
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# turn on NEMD shear and equilibrate some more
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velocity all scale $t
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# shear rate defined relative to perpendicular dimension
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variable xyrate equal ${srate}/ly
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fix 1 all nvt/sllod temp $t $t 0.1
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fix 2 all deform 1 xy erate ${xyrate} remap v
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compute layers all chunk/atom bin/1d y center 0.05 units reduced
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fix 4 all ave/chunk 20 250 5000 layers vx file profile.nemd.2d
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compute usual all temp
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compute tilt all temp/deform
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thermo 1000
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thermo_style custom step temp c_usual epair etotal press pxy
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thermo_modify temp tilt
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run 50000
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# data gathering run
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variable visc equal -pxy/(v_srate/ly)
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fix vave all ave/time 10 100 1000 v_visc ave running start 56000
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thermo_style custom step temp press pxy v_visc f_vave
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thermo_modify temp tilt
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# only need to run for 5400 steps to make a good 100-frame movie
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# set 54K steps above in equil and 5400 here simply to make good movie
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# 54K and 5400 are multiples of box-swap periodicity = 2700 steps
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#dump 1 all custom 50 dump.nemd.2d id type x y z vx
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#dump 2 all image 50 image.*.jpg vx type zoom 1.2 adiam 1.2
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#dump_modify 2 pad 5 amap 0.0 ${srate} ca 0.0 2 min blue max red
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run 50000
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