Hello all, I tried to simulate the free expansion of two layers in aqueous solution using LAMMPS. I used the “fix setforce 0 0 NULL” to make both layers only move in the z-direction. And I used the “fix 7 all npt temp 300 300 (100 * dt) aniso 1 (1000 * dt)” to control pressure, the average pressure output by “thermo_style press” was about “20”, but both layers kept crossing boundaries in the z-direction, which I believe is an abnormal phenomenon.
I have reviewed similar issues on the forum and found that when I modify the command to “fix rigid1 MMT-OH rigid single force * off on torque * off off”, “neigh_modify exclude group MMT2-OH MMT2-OH”, “neigh_modify exclude group MMT1-OH MMT1-OH”, “fix 7 all npt temp 300 300 (100 * dt) aniso 1 (1000 * dt) dilate Mobile”, there are still the issues I mentioned above, and at this time, LAMMPS outputs the average value of the press was about “1300”.
I don’t know how to solve this problem, and I would be thankful if you make your comments about this issue.
Test.data (787.0 KB)
Test.in (152.2 KB)