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Re: [lammps-users] How stress is computed when forces are velocity dependent?
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Re: [lammps-users] How stress is computed when forces are velocity dependent?


From: Arham Amouei <arham.amouei@...24...>
Date: Thu, 12 Apr 2018 22:04:48 +0430

Thank you. I doubt if my question was conveyed well. According to your valuable paper, which was mentioned,

P = N k_B T / V + <W> / 3V,    (1)

where

W = -3V dU/dV .                       (2)

T in the first term of Eq. (1) depends on total kinetic energy, and I think the algorithm used to compute it is independent of whether the forces have direct velocity dependency or not.

Assuming that the forces are of the form F = -grad U({r}) + Z(v), where Z(v) is some function of particle's velocity, W as defined in Eq. (2) does not take account of Z(v), as if the forces are of the form F = -grad U({r}) .

Best regards,
Arham Amouei