References of "Geuzaine, Christophe"
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See detailCo-simulation of Electromagnetic Transients and Phasor Models: a Relaxation Approach
Plumier, Frédéric ULg; Aristidou, Petros; Geuzaine, Christophe ULg et al

in IEEE Transactions on Power Delivery (in press)

Co-simulation opens new opportunities to combine mature ElectroMagnetic Transients (EMT) and Phasor-Mode (PM) solvers, and take advantage of their respective high accuracy and execution speed. In this ... [more ▼]

Co-simulation opens new opportunities to combine mature ElectroMagnetic Transients (EMT) and Phasor-Mode (PM) solvers, and take advantage of their respective high accuracy and execution speed. In this paper, a relaxation approach is presented, iterating between an EMT and a PM solver. This entails interpolating over time the phasors of the PM simulation, extracting phasors from the time evolutions of the EMT simulation, and representing each sub-system by a proper multiport equivalent when simulating the other sub-system. Various equivalents are reviewed and compared in terms of convergence of the PM-EMT iterations. The paper also considers the update with frequency of the Thévenin impedances involved in the EMT simulation, the possibility to compute the EMT solution only once per time step, and the acceleration of convergence through a prediction over time of the boundary variables. Results are presented on a 74-bus, 23-machine test system, split into one EMT and one PM sub-system with several interface buses. [less ▲]

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See detailNumerical Properties of a Discontinuous Galerkin formulation for electro-thermal coupled problems
Homsi, Lina; Geuzaine, Christophe ULg; Noels, Ludovic ULg

in Papadrakakis, M.; Papadopoulos, V.; Stefanou, G. (Eds.) et al Proceedings of the VII European Congress on Computational Methods in Applied Sciences and Engineering, Crete Island, Greece, 5–10 June 2016 (2016, June 05)

Discontinuous Galerkin (DG) methods are attractive tools to integrate several PDEs in engineering sciences, due to their high order accuracy and their high scalability in parallel simulations. The main ... [more ▼]

Discontinuous Galerkin (DG) methods are attractive tools to integrate several PDEs in engineering sciences, due to their high order accuracy and their high scalability in parallel simulations. The main interest of this work is to derive a constant and stable Discontinuous Galerkin method for two-way electro-thermal coupling analyses. A fully coupled nonlinear weak formulation for electro-thermal problems is developed based on continuum mechanics equations which are discretized using the Discontinuous Galerkin method. Toward this end, the weak form is written in terms of energetically conjugated fields gradients and fluxes. In order to validate the effectiveness of the formulation and illustrate the algorithmic properties, a numerical test for composite materials is performed. [less ▲]

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See detailEfficient Computation of the Extrema of Algebraic Quality Measures for Curvilinear Finite Elements
Johnen, Amaury ULg; Geuzaine, Christophe ULg; remacle, Jean-François

Conference (2016, June)

The development of high-order computational methods for solving partial differential equations on unstructured grids has been underway for many years. Such methods critically depend on the availability of ... [more ▼]

The development of high-order computational methods for solving partial differential equations on unstructured grids has been underway for many years. Such methods critically depend on the availability of high-quality curvilinear meshes, as one bad element can degrade the solution in the whole domain. The usual way of generating curved meshes is to first generate a (high-quality) straight-sided mesh. Then, mesh entities that are classified on the boundaries of the domain are curved. This operation introduces a "shape-distortion" that should be controlled. Quality measures allow to quantify to which point an element is well-shaped. They also provide tools to improve the quality of meshes through optimization. In this work we propose an efficient method to compute several quality measures for curved elements, based on the Jacobian of the mapping between the straight-sided elements and the curved ones. Contrary to the approach presented in "A. Gargallo-Peiró, X. Roca, J. Peraire, and J. Sarrate. Distortion and quality measures for validating and generating high-order tetrahedral meshes. Engineering with Computers, pages 1–15, 2014.", which relies on an L2-norm over the elements, we compute the actual minimum and maximum of the local quality measure for each element. The method is an extension of previous works on the validity of those elements (A. Johnen et al., 2013). The key feature is that we can adaptively expand functions based on the Jacobian matrix and its determinant in terms of Bézier functions. Bézier functions have both properties of boundedness and positivity, which allow sharp computation of minimum or maximum of the interpolated functions. [less ▲]

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See detailProper orthogonal decomposition versus Krylov subspace methods in reduced-order energy-converter models
Hasan M.D., Rokibul; V. Sabariego, Ruth; Geuzaine, Christophe ULg et al

Speech/Talk (2016)

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See detailComparison of Nonlinear Domain Decomposition Schemes for Coupled Electromechanical Problems
Halbach, Alexandre ULg; Dular, Patrick ULg; Geuzaine, Christophe ULg

in IEEE Transactions on Magnetics (2016), 52(3),

The aim of this paper is to compare several domain decomposition schemes for nonlinear, coupled electromechanical problems. Both staggered and monolithic electrostatic/elastic formulations are considered ... [more ▼]

The aim of this paper is to compare several domain decomposition schemes for nonlinear, coupled electromechanical problems. Both staggered and monolithic electrostatic/elastic formulations are considered for the multiphysics problem. The domain decomposition is applied either to a single multiphysics iteration, which corresponds to a linear problem, or to the full nonlinear multiphysics resolution. In the latter, the problem solved at each domain decomposition iteration is nonlinear. The influence of the elastic wave’s frequency and the electrostatic potential on the convergence rate and the computational cost of the algorithm is investigated on a 2-D model of a vibrating micromembrane array. [less ▲]

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See detailDesign Sensitivity Analysis for Shape Optimization of Nonlinear Magnetostatic Systems
Kuci, Erin ULg; Henrotte, François; Duysinx, Pierre ULg et al

in IEEE Transactions on Magnetics (2016), 52(3),

The paper discusses the sensitivity analysis for the shape optimization of a nonlinear magnetostatic system, evaluated both by direct and adjoint approaches. The calculations rely on the Lie derivative ... [more ▼]

The paper discusses the sensitivity analysis for the shape optimization of a nonlinear magnetostatic system, evaluated both by direct and adjoint approaches. The calculations rely on the Lie derivative concept of differential geometry where the flow is the velocity field associated with the modification of a geometrical parameter in the model. The resulting sensitivity formulas can be expressed naturally in a finite element setting through a volume integral in the layer of elements connected to the surface undergoing shape modification. The accuracy of the methodology is analyzed on a 2D model of an interior permanent magnet motor (IPM), and on a 3D model of a permanent magnet system. [less ▲]

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See detailReduced Order Model for Accounting for High Frequency Effects in Power Electronic Components
Paquay, Yannick ULg; Geuzaine, Christophe ULg; Hasan, Md. Rokibul et al

in IEEE Transactions on Magnetics (2016)

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See detailNonlinear Interpolation on Manifold of Reduced Order Models in Magnetodynamic Problems
Paquay, Yannick ULg; Bruls, Olivier ULg; Geuzaine, Christophe ULg

in IEEE Transactions on Magnetics (2016), 52(3), 1-4

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See detailDomain Decomposition Methods for Time-Harmonic Electromagnetic Waves with High Order Whitney Forms
Marsic, Nicolas ULg; Waltz, Caleb; Lee, Jin-Fa et al

in IEEE Transactions on Magnetics (2016), 52(3),

Classically, domain decomposition methods (DDM) for time-harmonic electromagnetic wave propagation problems make use of the standard, low order, Nédélec basis functions. This paper analyzes the ... [more ▼]

Classically, domain decomposition methods (DDM) for time-harmonic electromagnetic wave propagation problems make use of the standard, low order, Nédélec basis functions. This paper analyzes the convergence rate of DDM when higher order finite elements are used for both volume and interface discretizations, in particular when different orders are used in the volume and on the interfaces. [less ▲]

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See detailGetDDM: an Open Framework for Testing Optimized Schwarz Methods for Time-Harmonic Wave Problems
Thierry, Bertrand; Vion, Alexandre; Tournier, Simon et al

in Computer Physics Communications (2016), 203

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See detailGeometrical validity of curvilinear pyramidal finite elements
Johnen, Amaury ULg; Geuzaine, Christophe ULg

in Journal of Computational Physics (2015), 299

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See detailSequential decision-making approach for quadrangular mesh generation
Johnen, Amaury ULg; Ernst, Damien ULg; Geuzaine, Christophe ULg

in Engineering with Computers (2015), 31(4), 729-735

A new indirect quadrangular mesh generation algorithm which relies on sequential decision-making techniques to search for optimal triangle recombinations is presented. In contrast to the state-of-art ... [more ▼]

A new indirect quadrangular mesh generation algorithm which relies on sequential decision-making techniques to search for optimal triangle recombinations is presented. In contrast to the state-of-art Blossom-quad algorithm, this new algorithm is a good candidate for addressing the 3D problem of recombining tetrahedra into hexahedra. [less ▲]

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See detailDesign Sensitivity Analysis for Shape Optimization of Nonlinear Magnetostatic Systems
Kuci, Erin ULg; Duysinx, Pierre ULg; Dular, Patrick ULg et al

in Proceedings of COMPUMAG 2015 (2015, June)

In this paper, a direct and an adjoint analytic sensitivity analysis for a nonlinear magnetostatic system is obtained, in the context of shape optimization for any design function. The calculations are ... [more ▼]

In this paper, a direct and an adjoint analytic sensitivity analysis for a nonlinear magnetostatic system is obtained, in the context of shape optimization for any design function. The calculations are based on the material derivative concept of continuum mechanics. The resulting sensitivity formula can be expressed as either a volume integral or as a boundary integral along the interface where shape modification occurs. A method for the calculation of the design velocity field and mesh updating scheme is introduced as well. The accuracy of the methodology is analysed on an inductor system, suggesting that the volume integration technique should be preferred. All methods are freely available for further testing in the open source environment GetDP/Gmsh. [less ▲]

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See detailComparison of Nonlinear Domain Decomposition Schemes for Coupled Electromechanical Problems
Halbach, Alexandre ULg; Dular, Patrick ULg; Geuzaine, Christophe ULg

in Proceedings of COMPUMAG 2015 (2015, June)

The aim of this paper is to compare several domain decomposition schemes for nonlinear, coupled electromechanical problems. Both staggered and monolithic electrostatic/elastic formulations are combined ... [more ▼]

The aim of this paper is to compare several domain decomposition schemes for nonlinear, coupled electromechanical problems. Both staggered and monolithic electrostatic/elastic formulations are combined with an overlapping domain decomposition method applied either to the uncoupled, linear staggered resolutions or to the monolithic nonlinear system. The influence of the elastic waves frequency, of the electrostatic potential and of the mesh on the convergence rate is investigated on a simple 2D model of a vibrating micromembrane array. [less ▲]

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See detailFinite element models for studying the capacitive behaviour of wound components
De Grève, Zacharie; Dular, Patrick ULg; Sabariego, Ruth V. et al

in Proceedings of COMPUMAG 2015 (2015, June)

Finite element models of increasing accuracy are proposed for the study of the capacitive behaviour of wound magnetic components. Simple models, which are based on the classical assumption of a decoupling ... [more ▼]

Finite element models of increasing accuracy are proposed for the study of the capacitive behaviour of wound magnetic components. Simple models, which are based on the classical assumption of a decoupling between electric and magnetic fields, are first described. Formulations which enable such a coupling are then presented. The models are tested on various coreless inductors, made of round conductors or copper sheets. The results are discussed and compared with experimental data measured with an impedance analyzer. [less ▲]

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