Regarding boundary condition for a system in which gravity present.

Dear All,
I am doing simulation for a system in which different mass particles are present. When i

apply fix gravity command with periodic boundary conditions then whole frame moves with

given acceleration. In this case i have not seen effect of gravity on particles i. e. one region
particles not moves towards other region which have different mass due to gravity.
For seeing effect of gravity i have applied non-periodic boundary condition with reflected wall

in the direction of gravity. In this case i have seen that a shock is produced from reflecting wall
which effect the particles motion. I don’t want this shock effect the particles motion.

I want to know that from which boundary condition, i can see the effect of gravity

in which shock will also not present.

Thanks in advance.

Regards

Dear All,
I am doing simulation for a system in which different mass particles are
present. When i
apply fix gravity command with periodic boundary conditions then whole frame
moves with
given acceleration. In this case i have not seen effect of gravity on
particles i. e. one region
particles not moves towards other region which have different mass due to
gravity.
For seeing effect of gravity i have applied non-periodic boundary condition
with reflected wall
in the direction of gravity. In this case i have seen that a shock is
produced from reflecting wall
which effect the particles motion. I don't want this shock effect the
particles motion.
                    I want to know that from which boundary condition, i can
see the effect of gravity
in which shock will also not present.

it is practically impossible to give meaningful advice on such a vague
and unspecific description.
overall, it sounds as if the problem is that you are not setting up
your simulations correctly.

axel.

First of all i have used periodic boundary in all direction then not seen effect
of gravity. In next step for seeing effect of gravity i have used non-periodic bc

with reflecting wall in y- direction. For latter case code is given below:

2D NVT restart file

read_restart sks.restart.30000

The input below is just as nondescript and useless.

Axel

By the looks of these questions, I’d suggest reviewing some basic classical mechanics regarding center of mass and particle separation. On another note, Galileo explained the “effect of gravity” on particles of different masses pretty well.