Reading, United Kingdom
Reading, United Kingdom

OpenFOAM is a C++ toolbox for the development of customized numerical solvers, and pre-/post-processing utilities for the solution of continuum mechanics problems, including computational fluid dynamics . The code is released as free and open source software under the GNU General Public License. It is maintained by The OpenFOAM Foundation, which is sponsored by the ESI Group, the owner of the trademark to the name OpenFOAM. Wikipedia.

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Zerbib N.,ESI GROUP | Mebarek L.,ESI GROUP | Heather A.,OpenCFD | Mas D.,ESI FRANCE
23rd AIAA/CEAS Aeroacoustics Conference, 2017 | Year: 2017

The design of modern structure exterior like car, train or aircraft is mainly influenced by the aerodynamic performances. In automotive for example, the air flow detached from the A-pillar and impacting the side windows are of particular interest as they are close to the driver’s/passengers’ ears. The geometrical characteristics of the A-pillar can determine the size or strength of the vortex structure. For early optimized determination of the A-pillar, a very fast and accurate numerical methodology to predict the exterior noise due to the aero-acoustic sources, located in the wake of the side mirror and in the large turbulent region close to the side window and the A-pillar is needed. The new simulation method presented in that paper is a two-step approach assuming the decoupling of noise generation and propagation. The first stage consists in an incompressible Detached Eddy Simulation (DES) of the turbulent flow field. In that specific formulation, the equivalent aero-acoustic sources are represented only by the 3D volume hydrodynamic pressure instead of the more standard and well-known Lighthill’s tensor. In the second step, the acoustic propagation of those 3D volume sources is dealt with an hybridization between the Finite Element and the Boundary Element Methods (FEM/BEM) using an Adaptive Absorbing Boundary Condition (AABC) updated iteratively by a matrix-vector-product accelerated by the MultiLevel Fast Multipole Method (MLFMM). This method can be interpreted as a Domain Decomposition Method (DDM) with overlapping taking advantage of every numerical methods. To save CPU time and some space disk to store the aero-acoustic data, the CFD sources term is transferred from the CFD mesh to the acoustic mesh on the fly, i.e. at the end of each converged time step during the CFD computation by using a conservative mapping operator. Using an academic case, we calculate by this new formulation the sound generated by a turbulent flow over a sphere and we compare it to the standard Boundary Element Curle’s analogy. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.

Borg M.K.,University of Strathclyde | MacPherson G.B.,OpenCFD | Reese J.M.,University of Strathclyde
Molecular Simulation | Year: 2010

We present a new parallelised controller for steering an arbitrary geometric region of a molecular dynamics (MD) simulation towards a desired thermodynamic and hydrodynamic state. We show that the controllers may be applied anywhere in the domain to set accurately an initial MD state, or solely at boundary regions to prescribe non-periodic boundary conditions (PBCs) in MD simulations. The mean molecular structure and velocity autocorrelation function remain unchanged (when sampled a few molecular diameters away from the constrained region) when compared with those distributions measured using PBCs. To demonstrate the capability of our new controllers, we apply them as non-PBCs in parallel to a complex MD mixing nano-channel and in a hybrid MD continuum simulation with a complex coupling region. The controller methodology is easily extendable to polyatomic MD fluids. © 2010 Taylor & Francis.

Greenshields C.J.,OpenCFD | Reese J.M.,University of Strathclyde
Progress in Aerospace Sciences | Year: 2012

This paper investigates the use of Navier-Stokes-Fourier equations with non-equilibrium boundary conditions (BCs) for simulation of rarefied hypersonic flows. It revisits a largely forgotten derivation of velocity slip and temperature jump by Patterson, based on Grad's moment method. Mach 10 flow around a cylinder and Mach 12.7 flow over a flat plate are simulated using both computational fluid dynamics using the temperature jump BCs of Patterson and Smoluchowski and the direct simulation Monte-Carlo (DSMC) method. These flows exhibit such strongly non-equilibrium behaviour that, following Patterson's analysis, they are strictly beyond the range of applicability of the BCs. Nevertheless, the results using Patterson's temperature jump BC compare quite well with the DSMC and are consistently better than those using the standard Smoluchowski temperature jump BC. One explanation for this better performance is that an assumption made by Patterson, based on the flow being only slightly non-equilibrium, introduces an additional constraint to the resulting BC model in the case of highly non-equilibrium flows. © 2011 Elsevier Ltd. All rights reserved.

Ashton N.,University of Manchester | West A.,CD adapco | Mendonca F.,OpenCFD
21st AIAA/CEAS Aeroacoustics Conference | Year: 2015

This paper presents work to assess the noise emissions from a high-lift three-element airfoil using hybrid RANS-LES methods on both structured and unstructured meshes. The primary purpose of this work is to assess the sensitivity of the grid type and resolution using the same finite-volume code, numerical scheme and turbulence model. It has been shown that whilst the structured mesh provides better correlation to experimental data, an unstructured grid provides a good prediction of both the aerodynamic and acoustic data. The difierences between both meshes is generally small and explained by a combi- nation of mesh resolution, RANS/LES activation and numerical error. In particular, the initial separated shear layer is identified as the most challenging area to capture correctly. Furthermore estimates are made on the computational efiort to compute an entire aircraft using hybrid RANS-LES methods, based upon the spatial and temporal resolution of this work. © 2015, American Institute of Aeronautics and Astronautics Inc, AIAA. All Rights Reserved.

Wardle K.E.,Argonne National Laboratory | Weller H.G.,OpenCFD
International Journal of Chemical Engineering | Year: 2013

The flows in stage-wise liquid-liquid extraction devices include both phase segregated and dispersed flow regimes. As a additional layer of complexity, for extraction equipment such as the annular centrifugal contactor, free-surface flows also play a critical role in both the mixing and separation regions of the device and cannot be neglected. Traditionally, computional fluid dynamics (CFD) of multiphase systems is regime dependent - different methods are used for segregated and dispersed flows. A hybrid multiphase method based on the combination of an Eulerian multifluid solution framework (per-phase momentum equations) and sharp interface capturing using Volume of Fluid (VOF) on selected phase pairs has been developed using the open-source CFD toolkit OpenFOAM. Demonstration of the solver capability is presented through various examples relevant to liquid-liquid extraction device flows including three-phase, liquid-liquid-air simulations in which a sharp interface is maintained between each liquid and air, but dispersed phase modeling is used for the liquid-liquid interactions. © 2013 Kent E. Wardle and Henry G. Weller.

Greenshields C.J.,University of Strathclyde | Greenshields C.J.,OpenCFD | Weller H.G.,OpenCFD | Gasparini L.,Fondmetal Technologies S.r.l. | Reese J.M.,University of Strathclyde
International Journal for Numerical Methods in Fluids | Year: 2010

We describe the implementation of a computational fluid dynamics solver for the simulation of high-speed flows. It comprises a finite volume (FV) discretization using semi-discrete, non-staggered central schemes for colocated variables prescribed on a mesh of polyhedral cells that have an arbitrary number of faces. We describe the solver in detail, explaining the choice of variables whose face interpolation is limited, the choice of limiter, and a method for limiting the interpolation of a vector field that is independent of the coordinate system. The solution of momentum and energy transport in the Navier-Stokes equations uses an operator-splitting approach: first, we solve an explicit predictor equation for the convection of conserved variables, then an implicit corrector equation for the diffusion of primitive variables. Our solver is validated against four sets of data: (1) an analytical solution of the one-dimensional shock tube case; (2) a numerical solution of two dimensional, transient, supersonic flow over a forward-facing step; (3) interferogram density measurements of a supersonic jet from a circular nozzle; and (4) pressure and heat transfer measurements in hypersonic flow over a 25°-55° biconic. Our results indicate that the central-upwind scheme of Kurganov, Noelle and Petrova (SIAM J. Sci. Comput. 2001; 23:707-740) is competitive with the best methods previously published (e.g. piecewise parabolic method, Roe solver with van Leer limiting) and that it is inherently simple and well suited to a colocated, polyhedral FV framework. © 2009 John Wiley & Sons, Ltd.

ESI Group (Paris:ESI) (FR0004110310 – ESI), pioneer and leader in Virtual Prototyping solutions, today announces the acquisition of Scilab Enterprises SAS, publisher of Scilab, widely regarded as the most compelling open source alternative to MATLAB®1, the commercial software for analytical numerical solutions. Scilab provides a world class powerful environment for engineering computation and scientific applications. Commenting on this acquisition, Vincent Chaillou, ESI Group’s COO, said: “This acquisition fits perfectly with ESI Group’s technology investment strategy. It is aligned with our objective to expand our user base to include all stakeholders involved in the industrial product creation process, starting from the earliest stages of analytical modeling. It paves the way towards the more elaborate 3D-4D numerical simulations of the full Virtual Prototyping and eventually of the all-encompassing “Immersive Virtual Engineering” transformative solutions of Industry 4.0.” Raphaël Auphan, CEO of Scilab Enterprises, said: “We are very enthusiastic about joining ESI, a numerical simulation and Virtual Prototyping global leader, to bring Scilab to a wider range of industrial, academic and research players. Our shared vision will provide the engineering community with the latest generation of analytical solutions to meet current and future numerical simulation challenges." A global community with more than a million engineering users Scilab Enterprises was created in 2010 out of the Scilab Consortium, which was itself created in 2003 as part of an initiative backed by INRIA, the French National Institute for computer sciences and applied mathematics. Scilab (SCIentific LABoratory) is an open-source multiplatform analytical numerical computation software and scientific & engineering programming language. First introduced in 1980 it is now engaging an active community of over a million engineering users and development partners in diverse industries and in education. With its wide range of mathematical functions, graphic interfaces, graphs and algorithms, Scilab enables users to build their own applications for numerical analysis, system modeling, data analytics, optimization, signal and image processing, embedded and control systems, up to test and measurement interfaces. Beyond publishing Scilab and offering Scilab consulting services, Scilab Enterprises offers as well “Scilab Cloud” for the web deployment in Software as a Service (SaaS) mode of scientific and engineering applications. This enables organizations and individuals to publish and manage the web-based use of their own Scilab applications. Thanks to its ability to interconnect with third-party codes, technologies and applications, Scilab can also serve as a single scientific and technical computing platform. Building on that capability Scilab Enterprises now offers a scientific and technological “Platform as a Service” (PaaS) to enable countless numbers of public and private enterprises as well as individual engineers and scientists to monetize applications written in different programming languages by facilitating their distribution, back-up and use. Importantly, applications exploiting Scilab’s many computational functions can be accessed by an unlimited number of users as the software is open source. A powerful vector for the democratization of ESI Group’s Virtual Prototyping and Immersive Virtual Engineering solutions The acquisition of Scilab will help expand ESI Group’s footprint in the product pre-design stage and early analytical phase. Starting with the recent acquisition of ITI, and its SimulationX (0D-1D) system modeling software, this expansion is part of the Group’s transformative and disruptive change strategy focused on front-loading the power of computer modeling to everyone involved in the product development process. Already engineers working in the frame of conventional “Product Lifecycle Management” (PLM) benefit from use of mathematical analytical models, built around Scilab, to quickly explore design options with simple (0D) models, before embarking into detailed (0D-1D to 3D-4D) modeling based design, certification and production. In ESI’s PLM disruptive vision, the next step to Virtual Prototyping is to follow the life of the product after its development and certification phases, to cover its actual, real life in operation. Now within the new methodological approach of the “Product Performance Lifecycle” (PPL) innovative modeling, the ‘as built’ Virtual Prototype is transformed into its “Hybrid Virtual Twin”, with ‘data driven’ updates from sensors in actual operations. Here mathematical models of the product - along with its real or virtual life sensors and control systems - are key to provide reliable predictive prototyping. In this fully “End to End” vision of innovative product development and subsequent piloting in real life operational conditions, the acquisition of Scilab Enterprises equips ESI to address the full spectrum of early engineering needs, from simple, but physically realistic models, all the way to the “as manufactured” and “as operated” virtual products that customers build today and develop for tomorrow assisted or autonomous products. Following ESI’s recent successful acquisition and integration of OpenCFD, specializing in developments and services for OpenFOAM®, an open source software for broad band numerical simulation in the field of Fluid Mechanics, this current operation substantiates the Group’s commitment to the open source business model to foster the disruptive moves that will democratize Virtual Engineering solutions “for all”. It will provide beneficiaries with greater freedom to customize applications and to tailor them to their own flexible and affordable needs. In this regard, Scilab’s incorporation into ESI’s global eco-system is expected to be a major catalyst in easing and speeding up the digital transformation of innovative industrial product development. Scilab Enterprises is naturally synergetic with ESI Group, both in technology and business opportunities. The existing ESI Cloud offering will be greatly boosted by this acquisition and by Scilab’s reputation with a very large global community of users in diverse industries and academic circles. It also represents a major asset that will help to increase ESI’s global visibility and eventually to unlock valuable commercial opportunities. Moreover, the dynamic presence of Scilab in the educational community worldwide will immediately expand ESI’s footprint in that all important sphere. Financial aspects of the operation The operation is being financed mainly by the transfer of some ESI Group treasury shares to the shareholders of Scilab Enterprises. Scilab’s development platform and team will be rapidly integrated into ESI’s operating structure. You can find all of our press releases at: As publisher of Scilab modeling and simulation software, Scilab Enterprises has a small expert team with a unique mix of applied mathematicians and computer science engineers. Scilab is an open source software used widely in the scientific & engineering community (100 000 downloads every month worldwide). Scilab is used for modeling & simulation and scientific post-processing in industrial companies as well as in education & research. Scilab Enterprises offers on the one hand professional services in numerical computing and on the other hand provides the Scilab Cloud platform for the cloud deployment of scientific and engineering applications. For more information, please visit ESI Group is a leading innovator in Virtual Prototyping software and services. Specialist in material physics, ESI has developed a unique proficiency in helping industrial manufacturers replace physical prototypes by virtually replicating the fabrication, assembly and testing of products in different environments. Coupled with Virtual Reality, animated by systems modeling, and benefiting from data analytics, Virtual Prototyping has become immersive, shared and interactive. ESI’s customers can bring their products to life, ensuring reliable ‘as built’ performance, serviceability and maintainability. ESI solutions help world-leading OEMs and innovative companies anticipate and make sure that their products will pass certification tests - before any physical prototype is built - and that their new products are competitive when entering their market space. Recently, ESI has undertaken a major transformative adaptation of its Virtual Prototyping solutions into “Hybrid Virtual Twins”, to enter the new paradigm of “Product Performance Lifecycle” (PPL), which addresses, beyond the development phase, the life of the new product in its full operational cycle from launch to retirement. Riding the new age of ubiquitous sensors connected to the Internet of Things (IoT), PPL answers the emerging needs of industrial manufacturers to relentlessly create innovative products that are smart, assisted and autonomous. ESI’s customer base spans major industry sectors. The company employs more than 1200 high-level engineers, scientists and domain specialists worldwide, to address the needs of customers in more than 40 countries. ESI Group is listed in compartment B of NYSE Euronext Paris and is granted “Entreprise Innovante” (Innovative Company) certification since 2000 by Bpifrance. ESI is eligible for inclusion in FCPI (venture capital trusts dedicated to innovation) and PEA PME. For more information, please visit

Vincent Chaillou, Directeur Général Délégué d’ESI Group, déclare : « Cette acquisition s’inscrit parfaitement dans la poursuite des investissements technologiques déjà réalisés par ESI Group. Elle est en ligne avec notre objectif qui vise à étendre notre base d’utilisateurs scientifiques à tous les acteurs impliqués dans la conception et la création de produits industriels dès la première étape de la modélisation analytique. Cette extension ouvre la voie vers les simulations numériques 3D-4D plus élaborées du Prototypage Virtuel et ultérieurement vers les solutions globales et transformatrices de «l’Ingénierie Virtuelle Immersive» de l’Industry 4.0 et de l’Outcome Economy. » Raphaël Auphan, Directeur Général de Scilab Enterprises déclare : « Nous sommes enthousiastes à l’idée de rejoindre ESI, un leader mondial de la simulation numérique et du Prototypage Virtuel, pour porter Scilab auprès d’un ensemble plus large d’acteurs industriels, académiques et de la recherche. Notre vision commune permettra d’apporter à la communauté des ingénieurs et autres scientifiques, des solutions analytiques de dernière génération pour répondre aux enjeux actuels et futurs de la simulation numérique. » Scilab est un produit open source de calcul numérique analytique multiplateformes et un langage de programmation scientifique au mieux de l’état de l’art. Introduit en 1980, Scilab rassemble aujourd’hui une communauté active de plus d'un million d'utilisateurs en ingénierie, ainsi que de nombreux partenaires de développement dans divers secteurs industriels ou éducatifs. Avec sa large gamme de fonctions mathématiques, d’interfaces graphiques, de graphes et d'algorithmes, Scilab permet aux utilisateurs de construire leurs propres applications pour l’analyse numérique, la modélisation des systèmes, l'analyse des données, l’optimisation, le traitement du signal et de l'image, les systèmes de contrôle embarqués et les tests et mesures. En plus d’être l’éditeur de Scilab, et le réalisateur de Services de conseil et d’expertise, Scilab Enterprises propose également la plateforme ‘Scilab Cloud’ pour le déploiement d'applications scientifiques et d’ingénierie en mode ‘Software as a Service’ (SaaS) permettant aux entreprises et aux scientifiques de publier et de gérer le déploiement web de leurs propres applications basées sur Scilab. Grâce à ses capacités d'interconnexion avec des progiciels, des technologies et des applications tierces, Scilab peut aussi jouer le rôle de plateforme unique. En effet Scilab Enterprises propose désormais une plateforme scientifique et technologique en tant que Service (‘Platform as a Service’ - PaaS) pour permettre à un nombre considérable d'entreprises publiques et privées et d’ingénieurs ou scientifiques de commercialiser des applications écrites dans différents langages de programmation en facilitant leur distribution, leur sauvegarde, leur utilisation et donc leur monétisation. Enfin, le logiciel étant basé sur un code source ouvert, les nombreuses fonctions de calcul de Scilab sont accessibles par un nombre illimité d'utilisateurs. L’acquisition de Scilab Entreprises contribuera à l’élargissement du positionnement d’ESI Group aux phases amont de la conception et de l’analyse des produits industriels. Initié dans ESI suite à l’acquisition d’ITI, et de son logiciel de modélisation des systèmes SimulationX (modèles de dimensions ‘0D-1D’), l’élargissement de ce positionnement s’inscrit dans la stratégie de transformation de rupture menée par le Groupe visant à apporter très tôt la puissance de la modélisation informatique à tous les intervenants du processus de développement des produits industriels. Les ingénieurs travaillant dans le cadre d’une approche traditionnelle de type PLM (Product Lifecylce Management) utilisent déjà des modèles mathématiques analytiques, construits à l'aide de Scilab, pour explorer rapidement les options de conception avec des modèles simplifiés (de dimension ‘0D’) avant d’entreprendre la conception détaillée avec des modèles plus raffinés (de dimensions ‘0D-1D’ à ‘3D-4D’), en vue de la certification puis de la mise en production de leurs produits. Dans l’approche de rupture poursuivie par ESI pour transformer le ‘Product Lifecycle Management’ (PLM) traditionnel, l’étape suivante du Prototypage Virtuel est de poursuivre la vie du produit au-delà des phases de développement et de certification, afin de couvrir sa vie réelle en fonctionnement opérationnel réel ou prévisionnel. Dans cette nouvelle approche méthodologique, intitulée «Product Performance Lifecycle» (PPL), le Prototype Virtuel ‘tel que fabriqué’ (‘as built’) est transformé en ‘Jumeau Virtuel Hybride’ (‘Hybrid Virtual Twin’) continument mis à jour par les données de capteurs ubiquistes pendant le fonctionnement réel ou hypothétique prévisionnel. Ici, les modèles mathématiques du produit - ainsi que ses capteurs réels ou virtuels et les systèmes de contrôle - sont essentiels pour fournir un prototypage prédictif fiable (‘data-driven’). Dans cette vision transformative du développement de bout en bout (‘end to end’) de produits innovants reliés à leur fonctionnement opérationnel, l'acquisition de Scilab Enterprises permet maintenant à ESI de répondre également aux premiers besoins techniques, à partir de modèles simples mais physiquement réalistes, avant d’évoluer vers les produits virtuels détaillés «tels que fabriqués» et «en fonctionnement» représentatifs des produits réels actuels construits par les clients, ou des produits assistés et autonomes de demain actuellement en développement. Après son acquisition réussie d’OpenCFD, société spécialisée en développements et services basés sur OpenFOAM®, également un logiciel open source pour la simulation numérique généralisée en mécanique des fluides, cette opération confirme l’engagement du Groupe pour le modèle économique open source et les changements transformationnels en faveur de la démocratisation des solutions d’ingénierie virtuelle. Cette approche permet de donner aux utilisateurs, avec des modalités flexibles et des coûts très abordables, une plus grande latitude en termes de personnalisation des applications et d’adaptabilité à leurs besoins. L´intégration de Scilab à l’écosystème mondial d’ESI devrait constituer, de ce fait, un levier majeur pour faciliter et accélérer la transformation numérique du développement de produits industriels innovants, connectés et intelligents. Scilab Enterprises et ESI Group bénéficieront naturellement des synergies tant en termes technologiques que commerciales. L'offre ESI Cloud actuelle sera grandement soutenue par cette acquisition et par la réputation de Scilab auprès d'une très grande communauté mondiale d'utilisateurs dans diverses industries et cercles académiques et de recherche. Elle représente également un atout majeur qui aidera à accroître la visibilité mondiale d'ESI et au final à créer de précieuses opportunités commerciales. En outre, la forte présence internationale de Scilab dans le domaine de l'éducation va immédiatement élargir la visibilité d'ESI dans ce secteur essentiel. En tant qu’éditeur du logiciel de modélisation et de simulation Scilab, Scilab Enterprises dispose d’une équipe resserrée d’experts composée de mathématiciens et d’ingénieurs informaticiens. Scilab est un logiciel open source largement utilisé parmi la communauté des scientifiques et ingénieurs (100 000 téléchargements chaque mois dans le monde). Le logiciel Scilab est utilisé pour la modélisation et la simulation et le post-traitement scientifique dans les entreprises industrielles mais également dans le secteur de l’éducation et de la recherche. Scilab Enterprises propose d’une part des services professionnels en calcul numérique et d’autre part met à disposition la plateforme ‘Scilab Cloud’ pour le déploiement d'applications scientifiques et techniques en mode Cloud. ESI Group est le principal créateur mondial de logiciels et services de Prototypage Virtuel. Spécialiste en physique des matériaux, ESI a développé un savoir-faire unique et innovant afin d’aider les industriels à remplacer les prototypes réels par des prototypes virtuels, leur permettant de fabriquer, assembler et tester leurs produits dans des environnements différents. Couplé à la Réalité Virtuelle, connecté à la modélisation des systèmes, et bénéficiant de l’analyse de données, le Prototypage Virtuel devient immersif, partagé et interactif : il permet aux clients d’ESI de mettre leurs produits à l’épreuve pour mieux garantir leur fiabilité et leur performance, et pour anticiper leur entretien et réparations. Les solutions d’ESI permettent aux grands donneurs d'ordres et aux entreprises innovantes d’anticiper et de s’assurer que leurs produits passeront les tests de certification – et ce, sans qu’aucun prototype réel ne soit nécessaire – les rendant plus compétitifs, dès leur arrivée sur le marché. Récemment, ESI a entrepris une adaptation transformante majeure de ses solutions de Prototypage Virtuel vers des « Jumeaux Hybrides Virtuels », pour entrer dans le nouveau paradigme du « Product Performance Lifecycle » (PPL). Le PPL aborde, au-delà de sa phase de développement, la nouvelle vie du produit dans son cycle complet de fonctionnement opérationnel, du lancement au retrait. Avec la nouvelle ère des capteurs omniprésents et connectés liés à l'Internet des objets (IoT), le PPL répond aux nouveaux besoins des industriels de créer sans relâche des produits innovants, intelligents, assistés et autonomes. ESI est présent dans les principaux secteurs industriels et emploie aujourd'hui plus de 1200 ingénieurs et scientifiques de haut-niveau à travers le monde, au service de ses clients répartis dans plus de 40 pays. ESI Group est une société française cotée sur le compartiment B d’Euronext Paris, labellisée « entreprise innovante » 2000 par Bpifrance (ex OSEO). ESI Group est éligible aux FCPI et aux PEA-PME.

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