Work

On the importance of numerical integration details for homogeneous flow simulation

Year: 2026

Type: article

Abstract: The Sllod equations of motion enable modeling of homogeneous flow at the atomic scale and are commonly used to predict fluid properties such as viscosity. However, few publicly available codes support such simulations, and those that do often include subtle problems in the numerical integration scheme or related aspects, which result in a failure to conserve the energy of the extended system. Here, we demonstrate a reversible and energy-conserving integration scheme for the Sllod equations of motion with error on the order of δt3, in line with typical operator splitting integrators used in standard molecular dynamics simulations. We discuss various implementation details and implement the scheme in LAMMPS, where we find that our changes enable more accurate simulation of transient responses, mixed flows, and steady states, especially at high rates of flow. Importantly, we show that a lack of energy conservation can manifest as a systematic error in the direct ensemble average of the pressure tensor, leading to an error in the calculated viscosity which becomes significant at high flow rates.

Source: The Journal of Chemical Physics

DOI: 10.1063/5.0315430

Authors: Stephen Sanderson, Debra J. Searles

Institution: The University of Queensland

Language: English

Topic: Advanced Physical and Chemical Molecular Interactions

Subfield: Physical and Theoretical Chemistry

Field: Chemistry

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,500

Funders: Australian Government, Government of Western Australia, Australian Research Council