On the importance of numerical integration details for homogeneous flow simulation

Fuente: arXiv
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Hauptverfasser: Sanderson, Stephen, Searles, Debra J.
Format: Preprint
Veröffentlicht: 2025
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author Sanderson, Stephen
Searles, Debra J.
author_facet Sanderson, Stephen
Searles, Debra J.
contents 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 do not implement a reversible numerical integration scheme or have other subtle problems. Here, we demonstrate a reversible and energy-conserving integration scheme for the Sllod equations of motion with error on the order of $δt^3$, 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.
format Preprint
id arxiv_https___arxiv_org_abs_2512_01318
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On the importance of numerical integration details for homogeneous flow simulation
Sanderson, Stephen
Searles, Debra J.
Soft Condensed Matter
Computational Physics
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 do not implement a reversible numerical integration scheme or have other subtle problems. Here, we demonstrate a reversible and energy-conserving integration scheme for the Sllod equations of motion with error on the order of $δt^3$, 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.
title On the importance of numerical integration details for homogeneous flow simulation
topic Soft Condensed Matter
Computational Physics
url https://arxiv.org/abs/2512.01318