It is 8 years since we launched CFD Direct to undertake the maintenance, production and release of OpenFOAM on behalf of the OpenFOAM Foundation, and provide support, training and cloud services to users of OpenFOAM. The Foundation is the copyright holder of OpenFOAM and exists to ensure its distribution exclusively as free, open source software under the General Public License (GPL) v3. CFD Direct does all the work for the Foundation to meet its objectives. For the tens of thousands of users that depend upon OpenFOAM, we summarise the principal activities of CFD Direct each year. Below is the summary for our 8th year, ending March 2023.

Development and Maintenance

Developments introduce new functionality to the software, which then must be maintained into the future. We undertook 967 man-hours of new developments, with 662 code commits to the public development line of OpenFOAM (OpenFOAM-dev), an increase of 30% from the previous year.

Maintenance is the essential redesign, repair and publishing work that adds minimal new functionality to the software, but instead targets the critical needs of users: accessibility, usability, robustness and extensibility. In year 8, we undertook 1162 man-hours of  maintenance work supported by 2022 maintenance funding at the OpenFOAM Foundation.

We released some very significant developments in OpenFOAM in Year 8.  Firstly, OpenFOAM v10 included Non-Conformal Coupling (NCC), a replacement for the Arbitrary Mesh Interface (AMI) and ACMI functionalities which are non-conservative and consequently unreliable for many problems. NCC maintenance continued well beyond the release of v10 to make it work seamlessly with MRF, second-order time schemes, mesh-to-mesh mapping, and ParaView.

In August 2022, we began to introduce modular solvers to OpenFOAM-dev which are written as classes, in contrast to the traditional application solvers, integral to OpenFOAM since 1993. Modular solvers are simpler to use and maintain than application solvers. Their source code is easier to navigate, promoting better understanding. They are more flexible; in particular, modules for different fluids and solids can be coupled across multiple regions, notably for conjugate heat transfer (CHT) with any type of flow, e.g. multiphase.

We continued the redesign of dynamic mesh functionality, motivated by the development of non-conformal coupling (NCC). The redesign specifically overcame a limitation of previous functionality which permitted only a single form of mesh motion or topological change within a simulation. Dynamic mesh also includes mapping of a solution to a specified sequence of pre-generated meshes during a simulation, for applications such as piston and valve motion in engines.

We resolved 147 issues on the Issue Tracking Site. Our strategy of effective OpenFOAM maintenance has reduced the number of unresolved issues to approximately 20.

OpenFOAM Foundation

Our other work for the OpenFOAM Foundation included the following:

OpenFOAM Training

At the beginning of Year 8, CFD Direct published a book for CFD with OpenFOAM. Entitled Notes on Computational Fluid Dynamics: General Principles, the book provides essential knowledge to perform CFD analysis with confidence. Thousands of CFD enthusiasts have accessed the book either online in HTML format free of charge and/or by purchasing a paperback copy for $29.95. Feedback on the book has been very positive.

We ran 63 days of OpenFOAM Training, updated for OpenFOAM v10, with our Essential CFD, Applied CFD and Programming CFD courses.  Courses were delivered as Virtual Training to the general public and hosted On-Site at companies. We updated all our courses to the latest version of OpenFOAM, rewriting topics such as rotating geometry (to include NCC), scalar transport and programming boundary conditions.

Our goal is to help participants learn effective CFD. Our focus is 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.

With the book providing the detailed, background information, our training material targets the workflows and processes to deliver robust CFD solutions.


CFD Direct From the Cloud™ (CFDDFC®) provides a turnkey platform including OpenFOAM v10 and related software, running in the cloud. CFDDFC has over 1000 subscribers running millions of core-hrs of AWS Elastic Cloud Compute (EC2). It allows low cost of running CFD in the cloud by using cheaper, spare capacity with EC2 Spot Instances, and enables users to rent hardware when needed, rather than purchasing, housing and administering the hardware on-premises.

In Year 8, we released Web CFD Direct From the Cloud (CFDDFC®), providing OpenFOAM which can be accessed from a remote desktop running in a web browser.  Web CFDDFC includes a command line interface (CLI) to manage instances, transfer CFD cases to and from instances, run OpenFOAM applications and connect via the browser desktop.

CFD Direct Year 8: 2022-2023
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