Help regarding applying forces on granular particles

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1

Hi all,

I am trying to apply a force on a simulation box with granular particles. I want it to apply like in the case where a piston pushes the topmost layer of particles towards the bottom and these particles then transmit the forces to nearby particles so that the particles come together at the bottom of the box to form a compact structure. I would like to get some suggestions as in how to achieve this.

Thanks in advance,
Muthukumar

2

How about using fix move?

3

Could fix wall/piston be used to achieve this? Since most fixes are applied on group of atoms, is it possible to apply the force on a single topmost atom and further applying force on other atoms only when the piston/wall reaches them without creating groups of atoms at the wall/piston boundaries?

Thanks,
Muthukumar

4

Could fix wall/piston be used to achieve this? Since most fixes are applied
on group of atoms, is it possible to apply the force on a single topmost
atom and further applying force on other atoms only when the piston/wall
reaches them without creating groups of atoms at the wall/piston boundaries?

please read the documentation, make a test, and find it out. that is
how research works.
please keep in mind that this is not [email protected]... :wink:

thanks,
     axel.

5

Could fix wall/piston be used to achieve this?
Sounds reasonable.

Since most fixes are applied on group of atoms, is it possible to apply the force on a single topmost atom and further applying force on other atoms only when the piston/wall reaches them without creating groups of atoms at the wall/piston boundaries?

Yes, granular potentials are local; so are walls.

6

Fix wall/gran already does something like this. It allows
the wall to move, just probably not in the manner you want.

You could an option/code to do a more general kind
of wall move, e.g. with a variable.

Steve