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Stefano Scialo - One of the best experts on this subject based on the ideXlab platform.
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a hybrid mortar virtual element method for discrete fracture network simulations
Journal of Computational Physics, 2016Co-Authors: Matias Fernando Benedetto, Stefano Berrone, Sandra Pieraccini, Andrea Borio, Stefano ScialoAbstract:The most challenging issue in performing underground flow simulations in Discrete Fracture Networks (DFN) is to effectively tackle the geometrical difficulties of the problem. In this work we put forward a new application of the Virtual Element Method combined with the Mortar method for domain decomposition: we exploit the flexibility of the VEM in handling polygonal meshes in order to easily construct meshes conforming to the traces on each fracture, and we resort to the mortar approach in order to "weakly" impose continuity of the solution on intersecting fractures. The resulting method replaces the need for matching grids between fractures, so that the Meshing Process can be performed independently for each fracture. Numerical results show optimal convergence and robustness in handling very complex geometries.
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a globally conforming method for solving flow in discrete fracture networks using the virtual element method
Finite Elements in Analysis and Design, 2016Co-Authors: Matias Fernando Benedetto, Stefano Berrone, Stefano ScialoAbstract:A new approach for numerically solving flow in Discrete Fracture Networks (DFN) is developed in this work by means of the Virtual Element Method (VEM). Taking advantage of the features of the VEM, we obtain global conformity of all fracture meshes while preserving a fracture-independent Meshing Process. This new approach is based on a generalization of globally conforming Finite Elements for polygonal meshes that avoids complications arising from the Meshing Process. The approach is robust enough to treat many DFNs with a large number of fractures with arbitrary positions and orientations, as shown by the simulations. Higher order Virtual Element spaces are also included in the implementation with the corresponding convergence results and accuracy aspects. HighlightsThe Virtual Element method allows for meshes made up by arbitrary polygonal elements.Guaranteed local and global conformity with no alteration of the geometry of the DFN.Unconstrained fracture-independent Meshing.Application of domain decomposition preconditioners.
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simulation of the steady state flow in discrete fracture networks with non conforming meshes and extended finite elements
Rock Mechanics and Rock Engineering, 2014Co-Authors: Stefano Berrone, Sandra Pieraccini, C Fidelibus, Stefano ScialoAbstract:In this paper a numerical method for the simulation of the steady-state fluid flow in discrete fracture networks is described. It is based on the use of non-conforming meshes, enrichment functions and an optimization procedure. The Meshing Process is performed on each fracture independently of the other fractures, i.e. without geometrical conformity at the intersections (traces). The slope discontinuities due to the flux exchange at the traces are then captured with the enrichment functions of the extended finite elements, and finally a functional is minimized by resorting to an optimization procedure. The method can be easily implemented for parallel computers being based on many small independent problems. In order to show the effectiveness of the method and the quality of the results, simulations of fluid flow in simple networks are illustrated.
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a pde constrained optimization formulation for discrete fracture network flows
SIAM Journal on Scientific Computing, 2013Co-Authors: Stefano Berrone, Sandra Pieraccini, Stefano ScialoAbstract:We investigate a new numerical approach for the computation of the three-dimensional flow in a discrete fracture network that does not require a conforming discretization of partial differential equations on complex three-dimensional systems of planar fractures. The discretization within each fracture is performed independently of the discretization of the other fractures and of their intersections. An independent Meshing Process within each fracture is a very important issue for practical large-scale simulations, making mesh generation easier. Some numerical simulations are given to show the viability of the method. The resulting approach can be naturally parallelized for dealing with systems with a huge number of fractures.
Stefano Berrone - One of the best experts on this subject based on the ideXlab platform.
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a hybrid mortar virtual element method for discrete fracture network simulations
Journal of Computational Physics, 2016Co-Authors: Matias Fernando Benedetto, Stefano Berrone, Sandra Pieraccini, Andrea Borio, Stefano ScialoAbstract:The most challenging issue in performing underground flow simulations in Discrete Fracture Networks (DFN) is to effectively tackle the geometrical difficulties of the problem. In this work we put forward a new application of the Virtual Element Method combined with the Mortar method for domain decomposition: we exploit the flexibility of the VEM in handling polygonal meshes in order to easily construct meshes conforming to the traces on each fracture, and we resort to the mortar approach in order to "weakly" impose continuity of the solution on intersecting fractures. The resulting method replaces the need for matching grids between fractures, so that the Meshing Process can be performed independently for each fracture. Numerical results show optimal convergence and robustness in handling very complex geometries.
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a globally conforming method for solving flow in discrete fracture networks using the virtual element method
Finite Elements in Analysis and Design, 2016Co-Authors: Matias Fernando Benedetto, Stefano Berrone, Stefano ScialoAbstract:A new approach for numerically solving flow in Discrete Fracture Networks (DFN) is developed in this work by means of the Virtual Element Method (VEM). Taking advantage of the features of the VEM, we obtain global conformity of all fracture meshes while preserving a fracture-independent Meshing Process. This new approach is based on a generalization of globally conforming Finite Elements for polygonal meshes that avoids complications arising from the Meshing Process. The approach is robust enough to treat many DFNs with a large number of fractures with arbitrary positions and orientations, as shown by the simulations. Higher order Virtual Element spaces are also included in the implementation with the corresponding convergence results and accuracy aspects. HighlightsThe Virtual Element method allows for meshes made up by arbitrary polygonal elements.Guaranteed local and global conformity with no alteration of the geometry of the DFN.Unconstrained fracture-independent Meshing.Application of domain decomposition preconditioners.
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simulation of the steady state flow in discrete fracture networks with non conforming meshes and extended finite elements
Rock Mechanics and Rock Engineering, 2014Co-Authors: Stefano Berrone, Sandra Pieraccini, C Fidelibus, Stefano ScialoAbstract:In this paper a numerical method for the simulation of the steady-state fluid flow in discrete fracture networks is described. It is based on the use of non-conforming meshes, enrichment functions and an optimization procedure. The Meshing Process is performed on each fracture independently of the other fractures, i.e. without geometrical conformity at the intersections (traces). The slope discontinuities due to the flux exchange at the traces are then captured with the enrichment functions of the extended finite elements, and finally a functional is minimized by resorting to an optimization procedure. The method can be easily implemented for parallel computers being based on many small independent problems. In order to show the effectiveness of the method and the quality of the results, simulations of fluid flow in simple networks are illustrated.
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a pde constrained optimization formulation for discrete fracture network flows
SIAM Journal on Scientific Computing, 2013Co-Authors: Stefano Berrone, Sandra Pieraccini, Stefano ScialoAbstract:We investigate a new numerical approach for the computation of the three-dimensional flow in a discrete fracture network that does not require a conforming discretization of partial differential equations on complex three-dimensional systems of planar fractures. The discretization within each fracture is performed independently of the discretization of the other fractures and of their intersections. An independent Meshing Process within each fracture is a very important issue for practical large-scale simulations, making mesh generation easier. Some numerical simulations are given to show the viability of the method. The resulting approach can be naturally parallelized for dealing with systems with a huge number of fractures.
Matias Fernando Benedetto - One of the best experts on this subject based on the ideXlab platform.
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a globally conforming method for solving flow in discrete fracture networks using the virtual element method
Finite Elements in Analysis and Design, 2016Co-Authors: Matias Fernando Benedetto, Stefano Berrone, Stefano ScialoAbstract:A new approach for numerically solving flow in Discrete Fracture Networks (DFN) is developed in this work by means of the Virtual Element Method (VEM). Taking advantage of the features of the VEM, we obtain global conformity of all fracture meshes while preserving a fracture-independent Meshing Process. This new approach is based on a generalization of globally conforming Finite Elements for polygonal meshes that avoids complications arising from the Meshing Process. The approach is robust enough to treat many DFNs with a large number of fractures with arbitrary positions and orientations, as shown by the simulations. Higher order Virtual Element spaces are also included in the implementation with the corresponding convergence results and accuracy aspects. HighlightsThe Virtual Element method allows for meshes made up by arbitrary polygonal elements.Guaranteed local and global conformity with no alteration of the geometry of the DFN.Unconstrained fracture-independent Meshing.Application of domain decomposition preconditioners.
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a hybrid mortar virtual element method for discrete fracture network simulations
Journal of Computational Physics, 2016Co-Authors: Matias Fernando Benedetto, Stefano Berrone, Sandra Pieraccini, Andrea Borio, Stefano ScialoAbstract:The most challenging issue in performing underground flow simulations in Discrete Fracture Networks (DFN) is to effectively tackle the geometrical difficulties of the problem. In this work we put forward a new application of the Virtual Element Method combined with the Mortar method for domain decomposition: we exploit the flexibility of the VEM in handling polygonal meshes in order to easily construct meshes conforming to the traces on each fracture, and we resort to the mortar approach in order to "weakly" impose continuity of the solution on intersecting fractures. The resulting method replaces the need for matching grids between fractures, so that the Meshing Process can be performed independently for each fracture. Numerical results show optimal convergence and robustness in handling very complex geometries.
P Ruegsegger - One of the best experts on this subject based on the ideXlab platform.
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finite element analysis of trabecular bone structure a comparison of image based Meshing techniques
Journal of Biomechanics, 1998Co-Authors: D Ulrich, Van Bert B Rietbergen, Harrie Weinans, P RuegseggerAbstract:In this study, we investigate if finite element (FE) analyses of human trabecular bone architecture based on 168 microm images can provide relevant information about the bone mechanical characteristics. Three human trabecular bone samples, one taken from the femoral head, one from the iliac crest, and one from the lumbar spine, were imaged with micro-computed tomography (micro-CT) using a 28 microm resolution. After reconstruction the resolution was coarsened to 168 microm. First, all reconstructions were thresholded and directly converted to FE-models built of hexahedral elements. For the coarser resolutions of two samples, this resulted in a loss of trabecular connections and a subsequent loss of stiffness. To reduce this effect, a tetrahedral element Meshing based on the marching cubes algorithm, as well as a modified hexahedron Meshing, which thresholds the image such that load carrying bone mass is preserved, were employed. For each sample elastic moduli and tissue Von Mises stresses of the three different 168 microm models were compared to those from the hexahedron 28 microm model. For one sample the hexahedron Meshing at 168 microm produced excellent results. For the other two samples the results obtained from the hexahedral models at 168 microm resolution were poor. Considerably better results were attained for these samples when using the mass-compensated or tetrahedron Meshing techniques. We conclude that the accuracy of the FE-models at 168 microm strongly depends on the bone morphology, in particular its trabecular thickness. A substantial loss of trabecular connections during the hexahedron Meshing Process indicates that poor FE results will be obtained. In this case the tetrahedron or mass-compensated hexahedron Meshing techniques can reduce the loss of connections and produce better results than the plain hexahedron Meshing techniques.
Sandra Pieraccini - One of the best experts on this subject based on the ideXlab platform.
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a hybrid mortar virtual element method for discrete fracture network simulations
Journal of Computational Physics, 2016Co-Authors: Matias Fernando Benedetto, Stefano Berrone, Sandra Pieraccini, Andrea Borio, Stefano ScialoAbstract:The most challenging issue in performing underground flow simulations in Discrete Fracture Networks (DFN) is to effectively tackle the geometrical difficulties of the problem. In this work we put forward a new application of the Virtual Element Method combined with the Mortar method for domain decomposition: we exploit the flexibility of the VEM in handling polygonal meshes in order to easily construct meshes conforming to the traces on each fracture, and we resort to the mortar approach in order to "weakly" impose continuity of the solution on intersecting fractures. The resulting method replaces the need for matching grids between fractures, so that the Meshing Process can be performed independently for each fracture. Numerical results show optimal convergence and robustness in handling very complex geometries.
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simulation of the steady state flow in discrete fracture networks with non conforming meshes and extended finite elements
Rock Mechanics and Rock Engineering, 2014Co-Authors: Stefano Berrone, Sandra Pieraccini, C Fidelibus, Stefano ScialoAbstract:In this paper a numerical method for the simulation of the steady-state fluid flow in discrete fracture networks is described. It is based on the use of non-conforming meshes, enrichment functions and an optimization procedure. The Meshing Process is performed on each fracture independently of the other fractures, i.e. without geometrical conformity at the intersections (traces). The slope discontinuities due to the flux exchange at the traces are then captured with the enrichment functions of the extended finite elements, and finally a functional is minimized by resorting to an optimization procedure. The method can be easily implemented for parallel computers being based on many small independent problems. In order to show the effectiveness of the method and the quality of the results, simulations of fluid flow in simple networks are illustrated.
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a pde constrained optimization formulation for discrete fracture network flows
SIAM Journal on Scientific Computing, 2013Co-Authors: Stefano Berrone, Sandra Pieraccini, Stefano ScialoAbstract:We investigate a new numerical approach for the computation of the three-dimensional flow in a discrete fracture network that does not require a conforming discretization of partial differential equations on complex three-dimensional systems of planar fractures. The discretization within each fracture is performed independently of the discretization of the other fractures and of their intersections. An independent Meshing Process within each fracture is a very important issue for practical large-scale simulations, making mesh generation easier. Some numerical simulations are given to show the viability of the method. The resulting approach can be naturally parallelized for dealing with systems with a huge number of fractures.