Coupling LAMMPS and OpenFOAM for Multi-Scale Models

Abstract

ARCHER2 training webinar,: Coupling LAMMPS and OpenFOAM for Multi-Scale Models presented online Wednesday 19th July 2023 14:00 - 16:00 BST. 89 slides available at: https://www.archer2.ac.uk/training/courses/230719-openfoam-lammps-vt/ . The next generation of science depends on solving the problem of linking simulations at different scales. In many physical processes, phenomena happening at the molecular scale determine the large-scale dynamics of the system. Boiling represents one such problem, where bubbles nucleating at the nanoscale depart from hot surfaces owing to fluid dynamics forces originating from millimetre-scale flow structures. To date, there is no existing modelling framework that can simultaneously capture all the relevant scales of this flow, that require molecular dynamics simulations at the nanoscale coupled with traditional continuum-scale techniques based on the control-volume formulation of the Navier-Stokes equations.

The objective of this project is to deliver a coupling platform, optimised for parallel computing, linking two popular molecular-scale and continuum-scale simulation tools that are already supported on ARCHER2, namely LAMMPS for molecular dynamics simulations (MD) and OpenFOAM for computational fluid dynamics (CFD) simulations. This will be achieved by extending the functionality of the coupling framework CPL library , developed by one of the investigators. The coupling is oriented towards the multi-scale simulation of nucleate boiling, where molecular dynamics resolves the near-wall field where nucleation occurs and continuum-scale fluid dynamics is used far from the wall where the bubble develops.

In this webinar, we:

- Introduce the project and the rationale behind MD-CFD coupling. - Present CPL library and the coupling framework. - Demonstrate how to evoke CPL library via the ARCHER2 module through examples including minimal dummy scripts, Couette flow and finally the full boiling case.