OpenFOAM is free, open source software in computational fluid dynamics for real-world engineering and scientific applications. CFD Direct is committed to maintain OpenFOAM, demonstrated by the thousands of code commits to OpenFOAM-dev, with support from contributors. Maintenance concerns the evolution of software in response to changes in user expectation and environment. We have introduced an agile strategy suitable to the feedback process of software evolution and have identified key areas of OpenFOAM that requiring significant redesign, e.g. AMI and particles.
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Cloud computing replaces large upfront expenses with low, variable payments that only apply to what you use. CFD simulations cover a range of sizes and complexity. Activity is generally interrupted by quiet periods when simulations are halted, e.g. when a simulation ends non-working hours, during analysis of results or preparation of a new simulation, etc. The fluctuating demand makes CFD well suited to a pay-per-use model. Users need to understand the costs involved to get the best value from cloud and be confident that they fall within budget. This article explains the costs, with an example of an external aerodynamics calculation with OpenFOAM using CFD Direct From the Cloud™ (CFDDFC) on Amazon Web Services (AWS).
A breakdown of outstanding issues in OpenFOAM (2016-10-26) shows 90% of unresolved issues falling within only 7 categories. The two worst offenders account for almost half of all unresolved issues: 1) AMI, ACMI and cyclic interfaces; and, 2) heat transfer, including conjugate heat transfer (CHT). These categories, and “particles and tracking” and “sources/constraints” in particular, require significant refactoring and/or rewriting. Their current state of disrepair was caused by poor funding under a roadmap development strategy. Funding of agile development of OpenFOAM is now needed to support our aim to improve quality, with a target 50% reduction in unresolved issues in 2017.
Agile development of OpenFOAM emerged following the public distribution of the development line in December 2014. It relies on user participation, which is encouraged by rewarding users for reporting issues with timely resolution. OpenFOAM was in poor health at version 2.3.0, with unresolved issues increasing rapidly and long resolution times. Following the move to agile development, unresolved issues are reduced and under control, with ~70% of issues resolved in 1 day and ~90% resolved in 1 week, taking OpenFOAM to a new level of quality and maturity (always releasable) by version 4.0.
The OpenFOAM Issue Tracking system exists to enable users to report issues. An issue exists when OpenFOAM behaves in a manner that does not meet reasonable expectations, including in design and usability. OpenFOAM is mature, quality software, whose successful development demands that issues are resolved in a timely manner. Roadmap development obstructs issue resolution, resulting in unreliable software and inefficient development. Instead, free, open source software can exploit agile development with frequent code release, as the best strategy for CFD development. Users should adopt continuous upgrade to minimize cost and to benefit the agile development strategy.
In 2017, CFD Direct are running sessions of their OpenFOAM Training courses — Essential CFD, Applied CFD and Programming CFD — fully updated with the latest features of the new version 4 release of OpenFOAM: 24-27 April 2017, Berlin Germany; 16-18 May, Virtual Asia-Pacific; 20-21 June, 26-27 June, Virtual Americas; 4-5 July, London UK; 12-13 Sept, Virtual Americas; 25-28 Sept, London UK; 16-19 October, Chicago USA. OpenFOAM v4 contains new functionality we introduced in OpenFOAM v4 to improve usability so our course participants spend less time struggling with quirks of the software, leaving more time to build and practice their CFD skills.
OpenFOAM version 4.0 is the latest major version of OpenFOAM, released on 28th June 2016. CFD Direct was by far the largest contributor to OpenFOAM 4.0, contributing the vast majority of new functionality including post-processing, numerous boundary conditions and physical models. Additionally, we contributed across all other aspects of software engineering that make OpenFOAM a mature, modern environment for CFD. This article provides the inside view of that work on the software engineering behind OpenFOAM 4.0, contributed largely during a 3 month period from April-July, 2016.
The OpenFOAM User Guide provides an introduction to OpenFOAM, through some basic tutorials, and some details about the general operation of OpenFOAM. OpenFOAM is a collection of approximately 250 applications built upon a collection of over 100 software libraries (modules). Each application performs a specific task, e.g the snappyHexMesh application can generate meshes for complex geometry, such as a vehicle. The simpleFoam application could then be used to simulate steady-state, turbulent, incompressible flow around the vehicle…
CFD Direct are pleased to announce a 4 day OpenFOAM Training Course in Beijing, China, 22-25 August 2016. The course involves demonstration of tasks from a range of scientific disciplines and industries from course modules of both the Essential CFD and Applied CFD courses. The instructor will be Chris Greenshields, co-founder of OpenFOAM, Director of CFD Direct & The OpenFOAM Foundation. The training will be in English, with assistance in Chinese translation from Dongyue Li, Beijing University of Chemical Technology.
On 25th March 2015, CFD Direct was launched by Henry Weller (creator of OpenFOAM), Chris Greenshields, and Jenya Collings. At the end of our first year, we summarise our principal activities as the primary contributor to OpenFOAM, producing 3 releases of OpenFOAM, maintaining the OpenFOAM code base, managing the OpenFOAM Foundation, creating a free documentation resource and engaging with the community. We launched 3 training courses — Essential, Applied and Programming CFD — which we deliver as scheduled classroom courses, live virtual training and on-site. We launched CFD Direct From the Cloud (CFDDFC), a complete CFD cloud computing platform using Amazon Web Services EC2.
During our first year, we made over 900 code commits to the to the public development line of OpenFOAM, making us by far the largest contributor of code to OpenFOAM. In 2015, we produced one major, one minor and one patch release of OpenFOAM. We carried out maintenance on OpenFOAM, reducing the number of outstanding issues by approximately 35%, involving over 500 commits to the bug fix line of OpenFOAM 3.0. We managed the OpenFOAM Foundation, established a free OpenFOAM documentation resource, and our posts on social media updated users about developments to OpenFOAM , which encouraged a strong community to support and contribute to OpenFOAM as free software.
In April 2015, we launched 2 × 2 day courses, Essential CFD and Applied CFD, which were delivered as scheduled classroom training courses in Berlin, Houston, London, Chicago and Munich. In early 2016 we launched our 2 day course, Programming CFD, which we are delivering initially as Live Virtual Training. Our 3 OpenFOAM Training courses, aimed at competency in CFD, are now run as scheduled classroom courses, live virtual training and on-site training. We believe our comprehensive, modern programme is the best OpenFOAM training, using only free, open source software, for a one-time investment in staff skills without recurring licence fees.
In 2015, we launched CFD Direct From the Cloud (CFDDFC), a complete OpenFOAM cloud computing platform that includes the latest version of OpenFOAM and supporting software running on Ubuntu. The platform provides OpenFOAM in its native Linux OS, which users can access directly from a terminal or via a remote desktop. CFDDFC is available for Amazon Web Services (AWS) as a product on AWS Marketplace, pre-configured for Amazon Elastic Compute Cloud (EC2). CFDDFC is in constant use, on a range of EC2 Instances ranging from the small instance, eligible for Free Tier, to the Compute Optimized instances including the largest with 36 virtual (18 physical) CPUs, and with multiple instances networked as a cluster for larger workloads.
OpenFOAM is free software, meaning users have the freedom to run, copy, distribute, study, change and improve the software. Users benefit from these freedoms, which account for much of OpenFOAM’s popularity. The OpenFOAM Foundation is the copyright holder of OpenFOAM, which it licenses exclusively under the GPL. It maintains a strong legal position to enforce the licence and preserve its freedoms, by being the single owner of OpenFOAM. This requires contributors to the project to assign copyright in their OpenFOAM contributions to it, through its Contributor Agreement. Organisations with a serious commitment to free software are signing the Agreement, including CFD Direct, blueCAPE, VTT Technical Research of Finland Ltd and Intel.
CFD Direct announces the release of Programming CFD, their new OpenFOAM Training course. The OpenFOAM programming course has been created by Chris Greenshields (OpenFOAM co-founder) and Henry Weller (OpenFOAM creator/architect). The course is 2 days duration and is initially available as Virtual Training in Europe and Americas time zones, with Chris Greenshields as instructor: 12-13 April 2016 – Europe; 19-20 April 2016 – Americas. The course teaches coding to OpenFOAM’s quality standards with tools to encourage good practice, developing code in small, digestible steps with periods of reflection to introduce new concepts.
In January-March 2016, CFD Direct are running sessions of their OpenFOAM Training courses — Essential CFD and Applied CFD — fully updated with the latest features of the new version 3.0 release of OpenFOAM: 25-28 January 2016, London UK; 22-25 February 2016, Houston USA; 7-10 March 2016, Berlin Germany. OpenFOAM v3.0 contains new functionality we introduced in OpenFOAM v3.0 to improve usability so our course participants spend less time struggling with quirks of the software, leaving more time to build and practice their CFD skills.
Anyone investing in OpenFOAM Training must want training that delivers the best return on their investment. It can be difficult to choose the best OpenFOAM training from the variety of disparate training offerings in a market that is particularly open due to the open source nature of the software. Questions should be asked of potential training providers to establish their credibility and experience in OpenFOAM and in CFD training. In this article we present 10 questions that might usefully be asked and present CFD Direct’s answers to the questions.
This article provides information on the equation describing conservation of energy relevant to fluid dynamics and computational fluid dynamics (CFD). It first assembles an equation for combined mechanical and thermal energy, i.e. total energy, in terms of material derivatives. It then presents an equation for thermal, or internal, energy. The total energy equation is then provided in terms of local (partial) derivatives, both in terms of internal energy and enthalpy. The implementation of the energy equation in solvers in OpenFOAM is then described.
Where is the Source Code? is a campaign to promote free, public distribution of OpenFOAM and software that links intimately to OpenFOAM. It is in response to a general dissatisfaction with the practice of making a modification to OpenFOAM, then promoting the benefits of the modification, without making that modification freely available to the public, often in order to sell it commercially. The campaign is simply to get people to ask “Where is the Source Code?” when modifications like this are promoted, for example after a conference presentation or in a response to a discussion on the Internet.
CFD Direct are running 2 pilot sessions of their new OpenFOAM Training courses on: 1-4 June 2015, Berlin, Germany; 15-18 June 2015, Houston, TX USA. The 2×2 day courses, Essential CFD and Advanced CFD, have been developed to enable people to deliver successful CFD solutions with OpenFOAM. The new courses are a result of 6 months development, built on our experience as the Architects of OpenFOAM and of training 2500 people with OpenFOAM.
An earlier article described the OpenFOAM training through which Jenya Collings and I provided almost 500 days of instructor-led, classes to 2,500 particpants. That training mainly described the workings of the OpenFOAM for the early adopters of the software, but we need training whose focus is to enable people to deliver successful CFD solutions. CFD Direct have developed this training over several months, with a modular format that addresses all components of CFD and where the participant learns through experience on a wide range of real-world CFD examples. The training is built on developments to OpenFOAM that make it easier to use, such as template cases, packaged tools, reorganised input and re-coded features.
In 2008, the Directors of CFD Direct began the first significant OpenFOAM Training courses. The training was written for early adopters of OpenFOAM at a time when OpenFOAM was far less functional than today. The courses largely emphasised how OpenFOAM worked and a lot of time was devoted to code customisation. We pioneered a convenient method of providing participants with a running version of OpenFOAM using a persistent live installation that booted Linux from an 8GB USB pendrive. The wider user community benefited from our example cases, e.g. the motorbike case, and code changes made for the courses becoming part of OpenFOAM and our adoption of Ubuntu leading to the release of OpenFOAM packaged for Ubuntu.
This article provides information on tensor mathematics, relevant to fluid dynamics and computational fluid dynamics (CFD). It describes scalars and vectors and typical algebraic vector operations. It follows with second rank tensors, their algebraic operations, symmetry, skewness and tensor invariants such as trace and determinant, higher rank tensors, co-ordinate system and change of axis. Tensor calculus is introduced (div, grad, curl and Laplacian), followed by integral theorems of Gauss and Stokes, with a physical representation of div and curl, and more.
This guide provides information and example terminal commands for Linux, relevant to users of OpenFOAM. Commands are written that refer to OpenFOAM, e.g. they include OpenFOAM Linux environment variables. Those commands that refer to OpenFOAM will only function as stated, if they are executed on a machine on which OpenFOAM is installed and the user’s environment variables are set up for OpenFOAM, e.g. as described in the source download page (see Setting Environment Variables).