The task of using molecular dynamics to determine the shear viscosity and the thermal conductivity of a model fluid is examined in detail for the Lennard-Jones fluid. The equilibrium time correlation function approach is compared with three nonequilibrium methods, Poiseuille Flow, Momentum Impulse Relaxation, and Reversed Perturbation Nonequilibrium Molecular Dynamics. The conventional wisdom is that the equilibrium approach requires very long simulation times in order to obtain statistically significant results. This study finds that only the Reversed Perturbation Nonequilibrium Molecular Dynamics method has the possibility of significantly reducing the simulation time required to obtain ``good'' estimates for the thermal conductivity. All of the reliable methods examined can produce accurate estimates for the shear viscosity with shorter simulationtimes than is needed for the determination of the thermal conductivity.
Citation: NIST Interagency/Internal Report (NISTIR) - 7170
NIST Pub Series: NIST Interagency/Internal Report (NISTIR)
Pub Type: NIST Pubs
Green Kubo, Lennard-Jones fluid, molecular dynamics, Poiseuille flow, reversed perturbation nonequilibrium, shear viscosity