It is 6 years since OpenFOAM co-founders Henry Weller and Chris Greenshields launched CFD Direct with Jenya Collings to oversee the maintenance of OpenFOAM, on behalf of the OpenFOAM Foundation, and provide support, training and cloud services to users of OpenFOAM. We summarise below our principal activities for our 6th year, ending March 2021.
Development
Developments introduce new functionality to the software, which then must be maintained into the future. We undertook 1216 man-hours of new developments, with 710 code commits to the public development line of OpenFOAM (OpenFOAM-dev). Customer projects funded ∼56% of the work, with CFD Direct bearing the remaining costs. Some examples of new developments include:
- new methods for interface capturing for multiphase flows;
- multicomponent transport models for heat and mass fluxes, e.g. FickianEddyViscosity with optional temperature-dependent coefficients;
- mixing rules for transport properties, e.g. Wilke;
- bespoke heatTransfer source term with heat transfer coefficient to an ambient temperature and heatSource source term for heat as a total power or power per unit volume.
Maintenance
Maintenance is the essential redesign, repair and publishing work that adds no new functionality to the software, but in instead targets the critical needs of users: accessibility, usability, robustness and extensibility. In year 6, we undertook 1268 man-hours of maintenance work supported by 2020 maintenance funding at the OpenFOAM Foundation. Significant redesigns of components of OpenFOAM include:
- replacement of fvOptions with fvModels for physical sources and fvConstraints for numerical constraints, with backward compatibility;
- new library for thermophysical transport modelling to enable complex energy and specie transport models, in particular multi-component diffusion;
- new library for momentum transport modelling which generalises shear-stress in the momentum equation, for incompressible and compressible Newtonian, non-Newtonian, visco-elastic laminar flow, Reynolds averaged and large-eddy simulation of turbulent flow.
We resolved 179 issues on the Issue Tracking Site, with improvements to the software including:
- fixing mesh distortion and bugs in patch indices and ordering in coupled (cyclic and processor) patches;
- in conjugate heat transfer, making the solid heat flux model both energy conservative and temperature consistent;
- improving the limiting of multiple phases in multiphaseEulerFoam.
Unresolved issues fell to a new low level during a sustained period of maintenance over the winter 2020 (see below). We aim to reduce these issues further following the release of some long term developments to fix fundamental problems in critical areas, e.g. AMI.
OpenFOAM Foundation
We continually manage the OpenFOAM Foundation, the copyright holder and licensor of OpenFOAM, to ensure it is distributed free and open source only. It provides a focal point for the supporters of OpenFOAM, including the organisations who fund OpenFOAM through Maintenance Plans and individuals who contribute developments and maintenance. Our work for the Foundation included:
- producing the major OpenFOAM v8 release and subsequent v8 patch releases, accompanied by release notes and documentation;
- packaging the development line,
OpenFOAM-devregularly for Ubuntu, other Linux distributions, Windows and macOS; - publishing the openfoam.org website and the subdomain websites for Issue Tracking, Source Guide and Downloads;
- creating a Technical Guides resource, and assisting HZDR to create a Guide to CFD for Polydisperse Flows;
- managing open source licensing issues, e.g. the OpenFOAM Foundation Contributor Agreement and enforcement.
Training
We hosted 67 days of OpenFOAM Training, updated for OpenFOAM v8, with our Essential CFD, Applied CFD, and Programming CFD courses. Courses were delivered exclusively as Virtual Training in response to the travel and social restrictions of COVID-19 by re-scheduling classroom courses as Virtual Training. With these measures, we maintained the normal level of participation on our courses in 2020.
During 2021, demand for places has increased, with courses now full until September. Those courses will be updated to the latest version of OpenFOAM, which we continuously improve to help participants learn effective CFD. We teach tools to build CFD competency with the aim to give participants:
- the confidence to deliver a good solution with CFD, rather than freeze at the keyboard;
- repeatable procedures to deliver the next good solution in a timely manner;
- the understanding to recognise a good solution from a bad one.
Cloud
CFD Direct From the Cloud™ (CFDDFC®) provides a turnkey platform including OpenFOAM v8 and related software, running in the cloud. CFDDFC reached over 700 subscribers running millions of core-hrs of AWS Elastic Cloud Compute (EC2). It offers low cost of running CFD in the cloud by using cheaper, spare capacity with EC2 Spot Instances, and provides cost estimates for instances and data transfer. In 2021 CFD Direct progressed its cloud computing by:
- extending the range of deployment options by releasing CFDDFC v8 on the Microsoft Azure;
- releasing CFDDFC (Arm) for for Amazon EC2 instances running Arm-based Graviton2 processors;
- improving and extending the user documentation for running CFDDFC on AWS and running CFDDFC on Azure;
- achieving AWS High Performance Computing Competency (HPC) in recognition for deep experience in high performance computing