I am new to LAMMPS to get insight in to things I started with the examples but facing the following basic problem in understanding the examples (flow)
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How it is calculating the number of atoms (examples-flow -in.flow.poiss) . I calculated as Number den=no./vol therefore 0.7*(20*10)=140. and then multiplied by 3. from the create box command then it gives no. of atoms 420. but it doesn’t work for others example.
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How it is assigning 60 no. of atoms to lower and upper region.(please check in the output file) .
I gone through documentation but doesn’t got clear idea. Please help me in clearing the doubt.
input file
dimension 2
boundary p s p
atom_style atomic
neighbor 0.3 bin
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neigh_modify delay 5
create geometry
lattice hex 0.7
region box block 0 20 0 10 -0.25 0.25
create_box 3 box
create_atoms 1 boxmass 1 1.0
mass 2 1.0
mass 3 1.0LJ potentials
pair_style lj/cut 1.12246
pair_coeff * * 1.0 1.0 1.12246define groups
region 1 block INF INF INF 1.25 INF INF
group lower region 1
region 2 block INF INF 8.75 INF INF INF
group upper region 2
group boundary union lower upper
group flow subtract all boundaryset group lower type 2
set group upper type 3
OUTPUT FILE
dimension 2
boundary p s p
atom_style atomic
neighbor 0.3 bin
neigh_modify delay 5
create geometry
lattice hex 0.7
Lattice spacing in x,y,z = 1.28436 2.22457 1.28436
region box block 0 20 0 10 -0.25 0.25
create_box 3 box
Created orthogonal box = (0 0 -0.321089) to (25.6871 22.2457 0.321089)
1 by 1 by 1 processor grid
create_atoms 1 box
Created 420 atoms
mass 1 1.0
mass 2 1.0
mass 3 1.0
LJ potentials
pair_style lj/cut 1.12246
pair_coeff * * 1.0 1.0 1.12246
define groups
region 1 block INF INF INF 1.25 INF INF
group lower region 1
60 atoms in group lower
region 2 block INF INF 8.75 INF INF INF
group upper region 2
60 atoms in group upper
group boundary union lower upper
120 atoms in group boundary
group flow subtract all boundary
300 atoms in group flow
set group lower type 2
60 settings made for type
set group upper type 3
60 settings made for type