Reg: Nanoparticle aggregation in nanofluid

Dear Lammps users,

I am working on nanofluid thermal properties and trying to simulate the multi-nanoparticle system with water as a base fluid to see the aggregation effect over thermal properties.

when I put three nanoparticles within the simulation domain using PBC, nanoparticles moves and half of the nanoparticle comes from the other side of the domain (please see the attached picture).


  1. Can this be considered as the disintegration of nanoparticles?
  2. This is due to PBC, so can it be valid to simulate the multiparticle system.

Also please suggest how to stop this nanoparticle disintegration. Thank you in advance.

Attached are the initial configuration (t=0) and final configuration (t= 5 ns).



  1. No. This is just because your visualization software draws part of the particle in the top of the box and the other half in the bottom. As far as the simulation is concerned, this is equivalent with having the entire nanoparticle intact in either the top or bottom half of the box.
  2. Yes.

There is no good reason to prevent this other than for visualization, so I recommend checking out if your visualization software has options that allow for unwrapping across periodic boundaries or something.