OpenFOAM
OpenFOAM (for "Open-source Field Operation And Manipulation") is a C++ toolbox for the development of customized numerical solvers, and pre-/post-processing utilities for the solution of continuum mechanics problems, most prominently including computational fluid dynamics (CFD). There are three main variants of OpenFOAM software that are released as free and open-source software under the GNU General Public License Version 3. "In chronological order", these variants are as follows: History. The name FOAM has been claimed to appear for the first time as a post-processing tool written by Charlie Hill, in the early 90s in Prof. David  Gosman's group in Imperial College London. As a counter argument , it has been claimed that Henry Weller created the FOAM library for field operation and manipulation which interfaced to the GUISE (Graphical User Interface Software Environment) which was created by Charlie Hill for interfacing to AVS. Nevertheless, as a continuum mechanics / computational fluid dynamics tool, the first development of FOAM (which became OpenFOAM later on) was virtually always presumed to be initiated by Henry Weller at the same institute by using the C++ programming language rather than the de facto standard programming language FORTRAN of the time to develop  a powerful and flexible general simulation platform. From this initiation to the founding of a company called Nabla Ltd, (predominantly) Henry Weller and Hrvoje Jasak carried out the basic development of the software for almost a decade. For a few years, FOAM was sold as a commercial code by Nabla Ltd. However, on 10 December 2004, FOAM was released under GPL and was renamed to OpenFOAM. In 2004, Nabla Ltd was folded. Immediately afterwards, Henry Weller, Chris Greenshields and Mattijs Janssens founded OpenCFD Ltd to develop and release OpenFOAM. At the same time, Hrvoje Jasak founded the consulting company Wikki  Ltd and maintained a fork of OpenFOAM called openfoam-extend, later renamed to foam-extend. In April 2008, the OpenFOAM development moved to using git for its source code repository. On 8 August 2011, OpenCFD was acquired by Silicon Graphics International (SGI). On 12 September 2012, ESI Group announced the acquisition of OpenCFD Ltd, this company keeping its assets and notably the OpenFOAM trademark. In 2014, Weller and Greenshields left OpenCFD and formed CFD Direct Ltd. OpenFOAM Foundation Ltd whose directors are Henry Weller, Chris Greenshields, and Cristel de Rouvray (the CEO of the ESI Group) handed the maintenance of  the OpenFOAM-Foundation variant to CFD Direct. The following figure summarises the chronological and common development of the main three variants of OpenFOAM software, where the arrows show the directions of functionality transfers, namely: OpenFOAM Governance. In 2018, OpenCFD Ltd. and some of its industrial, academic, and community partners established an administrative body, i.e. OpenFOAM Governance, to allow the OpenFOAM's user community to decide/contribute the future development and direction of their variant of the software. The structure of OpenFOAM Governance consisted of a "Steering Committee" and various "Technical Committees". The Steering Committee comprised representatives from the main sponsors  of OpenFOAM in industry, academia, release authorities and consultant organisations. The organisation composition of the initial committee involved members from OpenCFD Ltd., ESI Group, Volkswagen, General Motors, FM Global, TotalSim Ltd., TU Darmstadt, and Wikki Ltd. In addition, nine technical committees were established in the following areas: Documentation, high performance computing, meshing, multiphase, numerics, optimisation, turbulence, marine applications, and nuclear applications with the members from the organisations of OpenCFD Ltd., CINECA, University of Zagreb, TU Darmstadt, National Technical University of Athens, Upstream CFD GmbH, University of Michigan, and EPFL. Structure. Software structure. The OpenFOAM layout consists of two main directories : Simulation structure. OpenFOAM simulations are configured by several plain text input files located across the following three directories: Additional directories can be generated, depending on user selections. These may include: