Computing bulk and shear viscosities from simulations of fluids with dissipative and stochastic interactions

Abstract

Exact values for bulk and shear viscosity are important to characterize a fluid and they are a necessary input for a continuum description. Here we present two novel methods to compute bulk viscosities by non-equilibrium molecular dynamics (NEMD) simulations of steady-state systems with periodic boundary conditions -- one based on frequent particle displacements and one based on the application of external bulk forces with an inhomogeneous force profile. In equilibrium simulations, viscosities can be determined from the stress tensor fluctuations via Green-Kubo relations; however, the correct incorporation of random and dissipative forces is not obvious. We discuss different expressions proposed in the literature and test them at the example of a dissipative particle dynamics (DPD) fluid.

arXiv comment8 pages, 7 figures. The following article has been accepted by Journal of Chemical Physics. After it is published, it will be found at http://scitation.aip.org/content/aip/journal/jcp

References in corpus (3)

• Static and Dynamic Properties of Dissipative Particle Dynamics
• Bulk viscosity of the Lennard-Jones system at the triple point by dynamical Non Equilibrium Molecular Dynamics
• New Green-Kubo formulas for transport coefficients in hard sphere-, Langevin fluids and the likes

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• Frequency-dependent Hydrodynamic Interaction Between Two Solid Spheres
• Custom Flow in Molecular Dynamics
• Dynamic Decay and Superadiabatic Forces in the van Hove Dynamics of Bulk Hard Sphere Fluids
• Thermodynamic formalism for transport coefficients with an application to the shear modulus and shear viscosity
• Hydrodynamic relaxations in dissipative particle dynamics
• Shear-thinning in Polymer Melts -- Molecular Origins and Hybrid Multiscale Simulations