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ARCHER2 Weekly Newsletter

By ARCHER2 Service on July 19, 2023

Tags: newsletters 

Coupling LAMMPS and OpenFOAM for Multi-Scale Models

Online webinar, Wednesday 19th July 2023 14:00 - 16:00 BST

Mirco Magnini and Gabriele Gennari (University of Nottingham), Edward Smith (Brunel University London), Gavin Pringle (EPCC, University of Edinburgh)

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 will:

  • 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.

Full details and join link

Parallel Performance Analysis using Scalasca

22 - 23 August 2023 09:30 - 16:30 BST in Oxford

Scalasca is a portable, free and open-source software tool that supports the performance optimisation of parallel programs by measuring and analysing their runtime behaviour. The analysis identifies potential performance bottlenecks – in particular those concerning communication and synchronisation – and offers guidance in exploring their causes. It uses execution profiles and traces generated by the community-developed Score-P instrumentation and measurement infrastructure.

Scalasca targets scientific and engineering applications based on the programming interfaces MPI and OpenMP, including hybrid applications using a combination of the two. The tool has been specifically designed for use on large-scale systems, but is also well suited for small and medium-scale HPC platforms. The software is available for free download under the New BSD open-source license.

This online course will cover how to use the tools in practice, delivered by members of the development team. Scalasca is portable across HPC systems, but for this course practical exercises will be conducted on the UK National HPC Service ARCHER2 (an HPC Cray EX system); all attendees will be given accounts on ARCHER2 for the duration of the course. Although example parallel programs will be provided, attendees are encouraged to analyse the performance of their own applications.

Full details and registration

Change to default version of ONETEP on ARCHER2

The default version of ONETEP on ARCHER2 was changed to a newer version onetep/6.1.43.0-CCE-LibSci on Mon 17 July 2023. The current default version is onetep/6.1.9.0-CCE-LibSci

If you wish to continue to use the older version after this change, you will need to change your job submission scripts to explicitly load the older version.

Recently added known issues

The “Known Issues” page of the ARCHER2 Documentation https://docs.archer2.ac.uk/known-issues/ lists all current open known issues including a description of the issue, its symptoms and any work-arounds.

  • No recent issues

Upcoming ARCHER2 Training

Further details of upcoming training

We always welcome researchers wishing to present their work in a webinar - please contact the Service Desk if you would be interested in presenting your work.

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Recordings of past courses

Recordings of past virtual tutorials