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lammps/examples/USER/sdpd/2d-diffusion-in-shear-flow/in.lammps
2018-10-30 17:40:00 +03:30

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dimension 2
units micro
atom_style meso
variable R equal 0.5 # radius of sphere micrometers
variable a equal $R/5 # lattice spacing micrometers
variable Lf equal $R*3
variable Lb equal $R*4
variable wall_velocity equal 0.01 # micrometers/microsecond
variable T equal 300.
variable rho_0 equal 1. # density picograms/micrometer^3
variable c_0 equal 100. # speed of sound micrometers/microsecond
variable mu equal 1. # dynamic viscosity picogram/(micrometer-microsecond)
variable h equal $a*4.5 # kernel function cutoff micrometers
variable mass equal $a*$a*$a*${rho_0}
variable dt equal 1e-3 # timestep microseconds
variable skin equal 0.2*$h
region box block -${Lb} ${Lb} -${Lb} ${Lb} 0 ${a} units box
create_box 4 box
lattice sq $a
create_atoms 1 box
region sphere sphere 0 0 0 $R units box
set region sphere type 2
region upper_wall block INF INF +${Lf} INF INF INF units box
set region upper_wall type 3
region lower_wall block INF INF INF -${Lf} INF INF units box
set region lower_wall type 4
group fluid type 1
group sphere type 2
group upper_wall type 3
group lower_wall type 4
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} ${h}
fix 1 fluid meso
fix 2 sphere rigid/meso single
fix 3 upper_wall meso/move linear +${wall_velocity} 0 0 units box
fix 4 lower_wall meso/move linear -${wall_velocity} 0 0 units box
fix 2d all enforce2d
neighbor ${skin} bin
neigh_modify delay 0 every 1 check yes
timestep ${dt}
dump dump_id all atom 100 dump.lammpstrj
thermo 100
thermo_style custom step time nbuild ndanger
run 10000