So you are saying that the external force I applied on the center atom of the solid particle also contribute to the virial term in the per-atom stress calculation of the surrounding solvent. It might be the case as I didn’t consider that in my own implementation. But how does the contribution happen?
But even assume this is the case, should the influence of the external force have a radial symmetry to the center of the solid where the external force is applied? not just in z direction? or not just influence the Pzz component. (there is only phase in this case, only water and a solid)
Actually the purpose of the external force is to fix the solid in position but allow it to rotate. I try to set the force flags to off in the fix rigid command. But it didn’t work out. I think this is a good time to solve that too. I guess it has something to do with the heat source which is inside the pairwise force of DPD. So any suggestion to get around that? Then probably I can decouple the problem if I can throw away the external force.
Thanks a lot
Heng
2011-09-23