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