Laser beam using sph

Hello,
I use user-sph for modelling laser ablation. I want to use fix heat for this but need use it for particles which placed only on surface.This surface can have comlex geometry. How can I select particles on surface with established depth? Are there alternative ways to tune the laser beam?

Thanks in advance for your the answer.

Hello,
I use user-sph for modelling laser ablation. I want to use fix heat for this but need use it for particles which placed only on surface.This surface can have comlex geometry. How can I select particles on surface with established depth? Are there alternative ways to tune the laser beam?

fix heat can be applied to only a specific, predefined group of atoms
(as most fixes) and atoms can be further selected by choice of a
region id on the fix heat command line. since regions can be complex
composites of the elementary region styles, rather complex geometries
can be realized. for more details, please review the fix heat, and
region command documentation.

axel.

I investigated fix heat and region before writing, but thank you for the information.
I have substrate and any object (wire, for example). If direction of beam is 0 0 -1, that part of beam touch substrate and other part touch wire. How I can select group of atoms which placed on surface substrate and wire where the beam act?

Thanks in advance for your the answer.

вс, 30 дек. 2018 г. в 01:51, Axel Kohlmeyer <[email protected]…43…4…>:

I investigated fix heat and region before writing, but thank you for the information.
I have substrate and any object (wire, for example). If direction of beam is 0 0 -1, that part of beam touch substrate and other part touch wire. How I can select group of atoms which placed on surface substrate and wire where the beam act?

i don't think that you can assume, that only the top layer of
particles (not sure if you can talk about atoms when using an SPH
model) will absorb the heat (you also have to allow for dissipation),
and i don't think that you can assume, that there is no
scattering/reflection of the beam. so i think using a sufficiently
large spherical region with the center close to the surface should do
the trick.
this is all in a rather approximate context, so i don't think it is
worth being very picky here.

axel.