Hi,
I am a new user to LAMMPS. I am trying to simulate a hydrodynamic
instability using MD, but I get the error at the second iteration that
there are lost atoms. After setting the command 'thermo_modify lost
ignore flush yes' the MD simulation went well, however the number of
atoms reduced from 20,000 to 13,000 in 100,000 iteration! where do
they go? Per se, I didn't find any other error. Could you please
elaborate on this error and a possible solution. I have two of the 2D
boxes sides as walls (no errors if all are periodic) as you can see in
my input file below.
Thanks in advance,
Elbert
Have you viz'd the atoms to see where they are going?
You say you have walls, but I don't see them defined.
You have a fixed BC in y, which means if atoms move
past the y boundaries they will be lost. What's preventing
the atoms from doing that?
Steve
Steve,
Thanks. The boundary 'f' is not appropriate for my case, so I tried
using of shrink-wrapping boundaries s and m. I tried using 'm' but
yet the box boundary seems (boundary p m p) to change in the
y-direction with time. From the manual, I understand that the fixing
of the boundary differentiates 'm' from 's'.
For the fluid instability case, I want to have the y-boundary walls
fixed (ie. restrain atoms between ymin and ymax) and either to reflect
or stick atoms that move out of y bounds. Please let me know an
appropriate way to specify this. An example would be better.
Thanks in advance,
Elbert
In LAMMPS, boundaries are not walls. If you want
to constrain the atoms, you need to use one of
the fix wall commands.
Steve