Multiscale Approach to Fluid-Solid Interfaces: An overview of methodologies coupling fluid mechanics to molecular dynamics and quantum theory

TL;DR

This paper reviews multiscale methodologies that integrate fluid mechanics with molecular dynamics and quantum theory to derive material-specific boundary conditions at fluid-solid interfaces.

Contribution

It provides an overview of coupling fluid mechanics with molecular and quantum approaches to improve boundary condition modeling.

Findings

Atomistic descriptions enable material-specific boundary conditions.

Molecular assessment of slip lengths informs macroscopic boundary conditions.

Quantum-derived force fields improve molecular dynamics simulations.

Abstract

In conventional fluid mechanics, the chemical composition and thermodynamic state of a fluid-solid interface are not considered when establishing velocity-field boundary conditions. As a consequence, fluid simulations are usually not able to generate different outputs when interfacial materials are varied. By considering an atomistic description of matter, theoretical determination of material-specific boundary conditions becomes possible, thereby providing an improved alternative to the completely-invariant no-slip condition. Such a scheme constitutes a multiscale approach to fluid dynamics involving essentially two transitions between space-time scales: the first concerns the derivation of macroscopic boundary conditions by means of molecular assessment of slip lengths; the second concerns the construction of interatomic force fields, required by molecular dynamics simulations, from quantum theory. In this introductory overview we discuss some of the fundamental aspects of these problems.