fix wall/gran

Submitted by DAVID RIVERA TAPIA on Mon, 10/28/2013 - 04:46

Hi everybody,

In the new version of liggghts I can not create a cylindrical wall with fix wall/gran/hertz/history. I am using this code to specify the cylwall:

fix cylwalls all wall/gran/hertz/history primitive type 1 zcylinder 0.1 0. 0.7

Is there any error in this line?

Regards,

David

DAVID RIVERA TAPIA | Mon, 10/28/2013 - 16:23

I did not get an error, but the cylindrical walls did not stop the particles in the simulation box.

The boundaries are:

region reg block -0.1 0.1 -0.1 0.1 0 0.7 units box

All the particles exceed the limits and quit the simulation box.

Best Regards,

David

cstoltz | Mon, 10/28/2013 - 20:30

Are the particles actually penetrating the cylinder walls, or falling out of the bottom of the cylinder in the z-direction? Keep in mind that a primitive cylinder is just an infinitely long horizontal tube with no top/bottom. If you want to add those, you'll need additional primitives.

If the particles are blowing through the walls, most likely a timestep issue.

Regards,
Chris

DAVID RIVERA TAPIA | Mon, 10/28/2013 - 23:32

The particles are falling out of the bottom. Do I need to define a z plane in order to avoid the particles to go out the cylinder?

Best regards,

David

cstoltz | Tue, 10/29/2013 - 10:50

Yes. To create a completely enclosed cylinder using primitives, you need three primitives - the cylinder and two planes to represent the ends. See fix_wall_gran in the documentation.

Regards,
Chris

DAVID RIVERA TAPIA | Wed, 10/30/2013 - 04:34

Hi Chris,

Thank you very much, your answer helped me to solve my trouble.

Best Regards,

David