Slip and stress from low shear rate nonequilibrium molecular dynamics: The transient-time correlation function...

Area of Science:

• Computational physics
• Fluid dynamics
• Materials science

Background:

• Understanding fluid behavior under shear is crucial for tribology and rheology.
• Accurate computation of phase variables in confined fluids is challenging, especially at low shear rates.

Purpose of the Study:

• To derive and apply the transient-time correlation function (TTCF) for calculating phase variables in inhomogeneous confined fluids.
• To assess the accuracy and applicability of the TTCF method for atomistic simulations under shear flow.

Main Methods:

• Derivation of the TTCF expression for boundary-driven planar shear (Couette) flow.
• Nonequilibrium molecular dynamics simulations of atomistic fluids under constant pressure and volume.
• Application of TTCF to compute shear stress and slip velocity at low shear rates.

Main Results:

• The TTCF method significantly improves the accuracy of results compared to direct trajectory averaging.
• Demonstrated suitability of TTCF for computing shear stress and slip velocity at realistic low shear rates.
• Validated TTCF for investigating tribology and rheology of confined fluids at atomistic detail.

Conclusions:

• The TTCF formalism provides a highly accurate and efficient method for simulating fluid dynamics under shear.
• This work enables more precise studies of friction and flow behavior in confined systems.
• The TTCF method is a valuable tool for atomistic simulations in tribology and rheology.