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lammps/examples/PACKAGES/dpd-smooth/equipartition-verification/in.lammps
2021-06-29 20:25:18 -04:00

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dimension 3
units micro
atom_style meso
variable a equal 0.1 # lattice spacing micrometers
variable L equal $a*10
variable T equal 300.
variable kB equal 1.3806504e-8 # picogram-micrometer^2/(microsecond^2-Kelvin)
variable rho_0 equal 1. # density picograms/micrometer^3
variable c_0 equal 10. # speed of sound micrometers/microsecond
variable mu equal 1. # dynamic viscosity picogram/(micrometer-microsecond)
variable h equal $a*4.0 # kernel function cutoff micrometers
variable mass equal $a*$a*$a*${rho_0}
variable dt equal 5e-4 # timestep microseconds
variable skin equal 0.1*$h
region box block -$L $L -$L $L -$L $L units box
create_box 1 box
lattice sc $a
create_atoms 1 box
mass * ${mass}
set group all meso/rho ${rho_0}
pair_style sdpd/taitwater/isothermal $T ${mu} 76787 # temperature viscosity random_seed
pair_coeff * * ${rho_0} ${c_0} ${h}
variable vx_sq atom vx*vx
variable vy_sq atom vy*vy
variable vz_sq atom vz*vz
compute v_sq all reduce ave v_vx_sq v_vy_sq v_vz_sq
variable vx_sq_check equal c_v_sq[1]*${mass}/${kB}/$T
variable vy_sq_check equal c_v_sq[2]*${mass}/${kB}/$T
variable vz_sq_check equal c_v_sq[3]*${mass}/${kB}/$T
fix 1 all meso
neighbor ${skin} bin
timestep ${dt}
thermo 10
thermo_style custom step time v_vx_sq_check v_vy_sq_check v_vz_sq_check
run 200