OpenFOAM® Journal最新文献

{"title":"IKA-FLOW : A Flexible Body Overset Mesh Implementation for Fish Swimming","authors":"M. Coe, S. Gutschmidt","doi":"10.51560/ofj.v3.89","DOIUrl":"https://doi.org/10.51560/ofj.v3.89","url":null,"abstract":"Simulation of inertial aquatic swimmers requires fluid structure interactions with temporal body geometry deformation. In practice,  his results in a change of the computational domain boundaries that represent the ”swimmer.” These simulations are traditionally done  sing body-fitted mesh and mesh morphing methods, but have drawbacks of negative cell volumes and small time-steps to  account for the complex swimming motion. In contrast, the overset mesh method, also provided by OpenFOAM®, overcomes most of  the drawbacks of the mesh morphing method at the expense of interpolation error. The current OpenFOAM® overset motion library only supports rigid body motion and cannot be used to resolve a body undergoing undulation. A modified motion solver is presented that allows for the complex mesh motion of an overset mesh for four body-caudal fin (BCF) virtual swimmers. The results of this solver are compared with published data of body-fitted meshes. The effect of different simulation parameters (including number of solving iterations, time delay, and temporal resolution) is investigated. Additionally, a novel simulation and comparison of the Ostraciiform locomotion mode with Anguilliform, Carangiform, and Thunniform modes are made investigating the wake, drag and lift. It is concluded that fish undulation has a marked effect on reducing lift generation. Lastly, a comparison of turbulence models (Spalart-Allmaras, k − ω SST, and k − kL − ω) at multiple Reynolds numbers shows that all three models have similar performance at lower Reynolds numbers but diverge at higher numbers.","PeriodicalId":252778,"journal":{"name":"OpenFOAM® Journal","volume":"2003 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114210538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Extending the isoAdvector Geometric VOF Method to Flows in Porous Media","authors":"Konstantin Missios, N. Jacobsen, Kasper Moeller, J. Roenby","doi":"10.51560/ofj.v3.72","DOIUrl":"https://doi.org/10.51560/ofj.v3.72","url":null,"abstract":"We consider the interfacial flow in and around porous structures in coastal and marine engineering.* During recent years, interfacial flow through porous media has been repeatedly simulated with Computational Fluid Dynamics (CFD) based on algebraic Volume Of Fluid (VOF) methods [1] [2]. Here, we present an implementation of a porous medium interfacial flow solver based on the geometric VOF method, isoAdvector [3] [4]. In our implementation, the porous medium is treated without resolving the actual pore geometry. Rather, the porous media, pores, and rigid structure are considered a continuum and the effects of porosity on the fluid flow are modelled through source terms in the Navier-Stokes equations, including Darcy-Forchheimer forces, added mass force and accounting for the part of mesh cells that are occupied by the solid material comprising the skeleton of the porous medium. The governing equations are adopted from the formulation by Jensen et al. [1]. For the interface advection using isoAdvector, we also account for the reduced cell volume available for fluid flow and for the increase in the interface front velocity caused by a cell being partially filled with solid material. The solver is implemented in the open source CFD library OpenFOAM®. It is validated using two case setups: 1) A pure passive advection test case to compare the isolated advection algorithm against a known analytical solution and 2) a porous dam break case by Liu et al. [5] where both numerical and experimental results are available for comparison. We find good agreement with numerical and experimental results. For both cases the interface sharpness, shape conservation as well as volume conservation and boundedness are demonstrated to be very good. The solver is released as open source for the benefit of the coastal and marine CFD community (code repository https://github.com/InterFlowers/porousInterIsoFoam) and as of OpenFOAM-v2112 the new functionality is integrated in the official interIsoFoam solver. \u0000* This article is an updated version of the conference paper Missios et al. 2022 [6] presented at the Marine2021 conference.","PeriodicalId":252778,"journal":{"name":"OpenFOAM® Journal","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128920846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hybrid LES/RANS simulations of a 90° pipe bend using different CFD solvers","authors":"A. Ekat, A. Weissenbrunner, M. Straka, T. Eichler, K. Oberleithner","doi":"10.51560/ofj.v3.36","DOIUrl":"https://doi.org/10.51560/ofj.v3.36","url":null,"abstract":"In this study, the performance of several RANS and hybrid LES/RANS turbulence models along with different CFD solvers (ANSYS Fluent, OpenFOAM and RapidCFD) is tested in terms of their ability to reproduce the flow downstream of a 90° pipe bend. The focus is on the temporal mean profiles downstream of the bend up to approximately 31 times the pipe's diameter D. The turbulence models' accuracy is evaluated by means of performance indicators and flow profiles in comparison to LDA measurements. The results demonstrate that the use of RANS models is suitable as long as the location of interest is in the vicinity of the bend up to approximately 10 D downstream of the bend. With increasing distance, the accuracy of the RANS models decreases, and the use of hybrid LES/RANS models is recommended.Three hybrid LES/RANS models are tested: the stress-blended eddy simulation (SBES) model as well as the Spalart-Allmaras-based and the k-omega SST-based improved delayed detached eddy simulation (IDDES) models. All three models show enhanced results for a distance to the bend >10 D. Additionally, it is found that in this geometry configuration, the IDDES models require a transient inlet. The flow separation due to the redirection inside the bend is too weak to generate turbulent fluctuations and a fast transition to full LES mode in the separation region. Due to the turbulent excitation at the inlet, the RANS region downstream of the bend is distinctly reduced, resulting in an enhanced performance of the hybrid IDDES models.","PeriodicalId":252778,"journal":{"name":"OpenFOAM® Journal","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133609479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"OpenFOAM-preCICE: Coupling OpenFOAM with External Solvers for Multi-Physics Simulations","authors":"Gerasimos Chourdakis, David Schneider, B. Uekermann","doi":"10.51560/ofj.v3.88","DOIUrl":"https://doi.org/10.51560/ofj.v3.88","url":null,"abstract":"Multi-physics simulations, such as conjugate heat transfer or fluid-structure interaction, are often constructed completely in OpenFOAM. However, they can also be formed by coupling OpenFOAM to third-party simulation software via a coupling tool. This approach indirectly adds to the capabilities of OpenFOAM those of other simulation tools (such as physical models or discretization methods more fitting for specific applications), and allows building complex multi-physics simulations by connecting specialized single-physics codes. We present the OpenFOAM-preCICE adapter, a function object that enables standard OpenFOAM solvers to use the open-source, massively parallel coupling library preCICE, without requiring any code modifications. We review alternative coupling approaches, analyze our design decisions, peek into key implementation details, validate the adapter, study the effect on runtime, and give an overview of the growing community of users and contributors.","PeriodicalId":252778,"journal":{"name":"OpenFOAM® Journal","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123872972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Open-source Computational Model for Polymer Electrolyte Fuel Cells","authors":"N. Weber, Leon Knüpfer, S. Beale, W. Lehnert, U. Reimer, Shidong Zhang, P. Ferreira-Aparicio, Antonio M. Chaparro","doi":"10.51560/ofj.v3.50","DOIUrl":"https://doi.org/10.51560/ofj.v3.50","url":null,"abstract":"Open-source fuel cell models outmatch commercial codes in many important aspects. By providing the source code, reuse, modification and extension of the model and comparison with other codes becomes possible. With this motivation, we present a three-dimensional, steady-state, non-isothermal proton exchange membrane fuel cell model, implemented in the open-source finite volume library OpenFOAM® . At every stage of implementation, special care was taken to ensure a well documented, organised, and modular structure of the software. The resulting model suite can, and should, be extended with new sub-modules by the user. The main field of application, modelling of fuel cells from an engineering perspective, is demonstrated by simulating two different conventional polymer electrolyte fuel cells, operated at CIEMAT and Forschungszentrum Jülich, respectively.","PeriodicalId":252778,"journal":{"name":"OpenFOAM® Journal","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128505515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Semi-Automatic Approach Based on the Method of Manufactured Solutions to Assess the Convergence Order in OpenFOAM","authors":"Bruno Bruno, R. Costa, F. Chinesta, J. M. Nóbrega","doi":"10.51560/ofj.v2.75","DOIUrl":"https://doi.org/10.51560/ofj.v2.75","url":null,"abstract":"Code verification is an intricate and crucial part of code developed. Due to the nature of the partial differential equations being solved, an analytical solution might not exit. To prove that the code is solving the correct equations, the method of manufactured solutions (MMS) is the go to approach. In this method we create a forcing term to drive the solution to a predetermined function. \u0000By performing a mesh refinement study, we can verify if the code is solving correctly the governing equations. In this work, we present the procedure of MMS as well as a tool developed in an open-source software for symbolic computation of the forcing term, appropriate boundary conditions and error norm computation withing the OpenFOAM® framework.","PeriodicalId":252778,"journal":{"name":"OpenFOAM® Journal","volume":"191 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129322552","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Review on the Modelling of Wave-Structure Interactions Based on OpenFOAM","authors":"Luofeng Huang, Yuzhu Li, Daniela Benites-Munoz, C. Windt, Anna Feichtner, S. Tavakoli, J. Davidson, R. Paredes, Tadea Quintuna, E. Ransley, M. Colombo, Minghao Li, P. Cardiff, G. Tabor","doi":"10.51560/ofj.v2.65","DOIUrl":"https://doi.org/10.51560/ofj.v2.65","url":null,"abstract":"The modelling of wave-structure interaction (WSI) has significant applications in understanding natural processes as well as securing the safety and efficiency of marine engineering. Based on the technique of Computational Fluid Dynamics (CFD) and the open-source simulation framework - OpenFOAM, this paper provides a state-of-the-art review of WSI modelling methods. The review categorises WSI scenarios and suggests their suitable computational approaches, concerning a rigid, deformable or porous structure in regular, irregular, non-breaking or breaking waves. Extensions of WSI modelling for wave-structure-seabed interactions and various wave energy converters are also introduced. As a result, the present review aims to help understand the CFD modelling of WSI and guide the use of OpenFOAM for target WSI problems.","PeriodicalId":252778,"journal":{"name":"OpenFOAM® Journal","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116908380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Towards the Numerical Modelling of Residual Seabed Liquefaction Using OpenFOAM","authors":"Ranjith khumar Shanmugasundaram, H. Rusche, C. Windt, Özgür Kirca, Mutlu Sumer, N. Goseberg","doi":"10.51560/ofj.v2.56","DOIUrl":"https://doi.org/10.51560/ofj.v2.56","url":null,"abstract":"Knowledge of the interaction between free surface waves and the seabed is required for the reliable design of marine structures, preventing severe structural failures. To that end, this paper presents the numerical modelling of wave-induced residual liquefaction of seabed soil. An OpenFOAM® finite volume solver is developed to simulate the behaviour of pore pressure and shear stress in the soil and is validated against analytical reference data. The soil is considered as a poro-elastic solid and an additional equation is solved for the pore pressure buildup. The governing equations are valid only up to the onset of liquefaction. A criterion based on the accumulated pore pressure is applied in order to predict the onset of residual liquefaction. The results show that the pore pressure and shear stresses are in good agreement with the analytical results and the relative errors are less than three percent. Also, the numerical results indicate that the wave induced residual liquefaction originates from the mudline and progresses slowly down the soil which is consistent with the analytical results. The pore pressure buildup for a seabed with stone columns shows that the liquefaction potential is very low near the stone column.","PeriodicalId":252778,"journal":{"name":"OpenFOAM® Journal","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122841748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"rom.js/cfd.xyz: An open-source framework for generating and visualizing parametric CFD results","authors":"C. Peña-Monferrer, Carmen Díaz-Marín","doi":"10.51560/ofj.v2.83","DOIUrl":"https://doi.org/10.51560/ofj.v2.83","url":null,"abstract":"We present in this technical note an open-source web framework for the generation and visualization of parametric OpenFOAM simulations from surrogate models. It consists of a JavaScript module (rom.js) and a web app (cfd.xyz) to explore fluid dynamics problems efficiently and easily for a wide range of parameters. rom.js is a JavaScript port of a set of open-source packages (Eigen, Splinter, VTK/C++ and ITHACA-FV) to solve the online stage of reduced-order models (ROM) generated by the ITHACA-FV tool. It can be executed outside a web browser within a backend JavaScript runtime environment, or in a given web solution. This methodology can also be extended to methods using machine learning. The rom.js module was used in cfd.xyz, an open-source web service to deliver a collection of interactive CFD cases in a parametric space. The framework includes some tutorials, showing the whole process from the generation of the surrogate model to the web browser. It also includes a standalone web tool for visualizing users' ROMs by directly dragging and dropping the output folder of the offline stage. Beyond the current proof of technology, this enables a collaborative effort for the implementation of OpenFOAM surrogate models in applications demanding real-time solutions such as digital twins and other digital transformation technologies.","PeriodicalId":252778,"journal":{"name":"OpenFOAM® Journal","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133125932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coupled Actuator Line and Finite Element Analysis Tool","authors":"P. Schmitt, D. Robinson","doi":"10.51560/ofj.v2.51","DOIUrl":"https://doi.org/10.51560/ofj.v2.51","url":null,"abstract":"Fluid-dynamic loading of many solid bodies can be simulated using geometry resolving computational fluid dynamics methods, where the body's shape is resolved in the mesh. In some cases though slender bodies, like ropes or cables, spars, turbine blades, foils and lattice structures would require prohibitively high cell counts, since the geometrical features to be resolve are much smaller than the overall domain. Such bodies are usually made up of generic cross sections like round, square or standardised technical profiles like the famous NACA digit series for which good parametrisations of reaction forces to incoming flow exist. Actuator line methods apply inflow dependent reaction forces to the fluid domain, thus allowing the computationally efficient simulation of slender bodies and have been used extensively, for example in wind and tidal turbine simulations. Beam elements representing slender bodies are standard building blocks in structural finite element models. Combining actuator line theory with a finite element beam model allows the efficient simulation of flexible structures under fluid loads, like turbine blades or nettings used in fish farms. This paper presents an implementation of such a coupled model in OpenFOAM based on the existing turbineFoam actuator line model. The underlying numerical method is detailed and first test cases are provided.","PeriodicalId":252778,"journal":{"name":"OpenFOAM® Journal","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126891539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}