OpenFPCI: A parallel fluid–structure interaction framework

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This paper presents OpenFPCI, a framework for coupling the C++ toolbox OpenFOAM-Extend, a computational fluid dynamics package, with the general purpose finite element package ParaFEM, written in Fortran and used to solve structural mechanics problems. The coupling of these two open source and scalable toolboxes, facilitates the use of high performance computing resources for the solution of fluid–structure interaction problems. The framework uses a master–slave approach, with OpenFOAM-Extend acting as the master and calling OpenFPCI plugins. The plugins are composed of a series of subroutines used to initialise and solve a specific engineering problem and make use of ParaFEM’s highly parallel implementation. The plugins are wrapped by C constructs such that OpenFOAM-Extend can call these Fortran subroutines consistently and when the solution from ParaFEM is required. Each plugin solves a different solid mechanics problem, with the current features including the deformation of a linear-elastic structure undergoing small strain and the deformation of a St. Venant–Kirchhoff material. Throughout this paper the focus will lie on the large strain plugin, considering the implementation and its validation for a benchmark problem, along with assessment of parallel capabilities, which are shown to scale to three thousand cores. This paper will be of interest to OpenFOAM and ParaFEM practitioners looking to utilise multiphysics simulations for their research, along with researchers looking to integrate fluid–structure interaction into their studies. Program summaryProgram Title:OpenFPCIProgram Files doi:http://dx.doi.org/10.17632/ntprzxk477.1Licensing provisions: BSD 2-ClauseProgramming language: Fortran, C and C++External libraries:OpenFOAM and ParaFEMSupplementary material: Example test cases are available within the OpenFPCI repository.Nature of problem: OpenFPCI was developed to solve computationally expensive fluid structure interaction problems by running on high performance computing systems. The framework was designed to enable the coupling of advanced ParaFEM capabilities to OpenFOAM-Extend.Solution method: OpenFOAM-Extend uses the classic Arbitrary Lagrangian–Eulerian formulation of the Navier–Stokes equations to deal with moving boundaries. The moving boundary is defined by using an OpenFPCI plugin, using ParaFEM’s libraries, to solve the deformation of the adjoining structure.