I have a question regarding the viscosity calculation based on Green-Kubo formula. My system consists of a spherical particle which is saturated in water confined between two moving rigid walls. Shear flow is applied to water as a result of sliding of the walls. First of all, is Green-Kubo formula is applicable to such an inhomogeneous formula? Second, the formula contains volume. Is this volume just the volume of water only or the volume of the whole system?

The values I’ve got for viscosity of water is 2 order of magnitudes larger than what is reported in the literature. I don’t know where is the problem. I checked the pressure of the system and it is on the order of 10 atm.

Steve,

I really appreciate for your helpful explanation. I could successfully implement the Green-Kubo formula into my input file.

Regards,

Farshad

The initial Q is what is you model for the wall. If it is just rigidly

moving atoms, you don’t need to thermostat them. You must

thermostat the fluid (water) because the dragging wall will

add energy to it. Langevin is a typical good choice. You can

look at the examples/VISCOSITY wall example for how

shear stress is measured - in that case in order to derive

a viscosity.

Steve