# Regarding problem in distributing particles uniformly inside wall

Hi All,
I am doing 2d simulation of Yukawa particles.

1. I have made wall of particles by creating a narrow region on edge.
I am also using neigh_modify exclude command for wall particles.
In position plot i see that particles are not uniformly distributed and
giving different magnitude of repulsive force at different places. How
i make uniform distribution of particles in wall ?

2. I have made wall only for ylo edge and using periodic boundary condition in that direction.
I have confusion that, this boundary condition is right ?

# Force field

pair_style yukawa 1.1962e3 0.011
pair_coeff * * 3.2790e-20

#Settings
neighbor 0.001 bin
neigh_modify every 1 delay 0 check yes exclude group wl wl

Hi All,
I am doing 2d simulation of Yukawa particles.

1. I have made wall of particles by creating a narrow region on edge.
I am also using neigh_modify exclude command for wall particles.
In position plot i see that particles are not uniformly distributed and
giving different magnitude of repulsive force at different places. How
i make uniform distribution of particles in wall ?

particles will be located where you place them, and unless you made a
mistake when immobilizing them, they'll stay there.

2. I have made wall only for ylo edge and using periodic boundary condition
in that direction.
I have confusion that, this boundary condition is right ?

it is your model, you have to know what it should look like.

Hi Lammps-Users,

I have distributed randomly 100 particles in wall and 10 particles in the simulation

and applied gravity in -y direction. simulation particles feel different magnitude
of repulsive force at different places of wall because of non- uniform distribution

of wall particles. Due to this different magnitude (balance of gravitational and
repulsive force), particles are not giving a line type structure and giving curve type

structure . You can see particle distribution in fig.,that is present in attachment.
How i find uniform distribution of particles in wall which will gives same magnitude
of force at all places.

Script

units si
atom_style atomic
dimension 2
boundary p p p

#Atom definition

distribution.eps (19 KB)

Hi Lammps-Users,

I have distributed randomly 100 particles in wall and 10 particles in the
simulation
and applied gravity in -y direction. simulation particles feel different
magnitude
of repulsive force at different places of wall because of non- uniform
distribution
of wall particles. Due to this different magnitude (balance of gravitational
and
repulsive force), particles are not giving a line type structure and giving
curve type
structure . You can see particle distribution in fig.,that is present in
attachment.
How i find uniform distribution of particles in wall which will gives same
magnitude
of force at all places.

LAMMPS will give you what you ask for. if you create a system with
particles at random locations it will behave like that. if you don't
want those particles be a different conformation, you have to adjust