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The aim of this work is to introduce and analyze a finite element discontinuous Galerkin method on polygonal meshes for the numerical discretization of acoustic waves propagation through poroelastic materials. Wave propagation is modeled by…

Numerical Analysis · Mathematics 2021-04-14 Paola F. Antonietti , Michele Botti , Ilario Mazzieri , Simone Nati Poltri

We present a new class of high-order accurate numerical algorithms for solving the equations of general-relativistic ideal magnetohydrodynamics in curved spacetimes. In this paper we assume the background spacetime to be given and static,…

Computational Physics · Physics 2018-05-28 Francesco Fambri , Michael Dumbser , Sven Köppel , Luciano Rezzolla , Olindo Zanotti

We develop and study a time-space discrete discontinuous Galerkin finite elements method to approximate the solution of one-dimensional nonlinear wave equations. We show that the numerical scheme is stable if a nonuniform time mesh is…

Analysis of PDEs · Mathematics 2021-04-07 Asma Azaiez , Mondher Benjemaa , Aida Jrajria , Hatem Zaag

We present and analyze a discontinuous Galerkin method for the numerical modelling of the non-linear fully-coupled thermo-poroelastic problem. For the spatial discretization, we design a high-order discontinuous Galerkin method on polygonal…

Numerical Analysis · Mathematics 2022-05-27 Paola F. Antonietti , Stefano Bonetti , Michele Botti

We explore whether a new method to solve the constraints of Einstein's equations, which does not involve elliptic equations, can be applied to provide initial data for black holes. We show that this method can be successfully applied to a…

General Relativity and Quantum Cosmology · Physics 2015-06-08 István Rácz , Jeffrey Winicour

We propose a new approach, based on the puncture method, to construct black hole initial data in the so-called trumpet geometry, i.e. on slices that asymptote to a limiting surface of non-zero areal radius. Our approach is easy to implement…

General Relativity and Quantum Cosmology · Physics 2009-10-20 Jason D. Immerman , Thomas W. Baumgarte

We present a new numerical tool for solving the special relativistic ideal MHD equations that is based on the combination of the following three key features: (i) a one-step ADER discontinuous Galerkin (DG) scheme that allows for an…

High Energy Astrophysical Phenomena · Physics 2015-08-12 Olindo Zanotti , Francesco Fambri , Michael Dumbser

The self-similar gravitational collapse solutions to the Einstein-axion-dilaton system have already been found out. Those solutions become invariants after combining the spacetime dilation with the transformations of internal SL(2, R). We…

General Relativity and Quantum Cosmology · Physics 2022-12-01 Ehsan Hatefi , Armin Hatefi

Binary black holes are the most abundant source of gravitational-wave observations. Gravitational-wave observatories in the next decade will require tremendous increases in the accuracy of numerical waveforms modeling binary black holes,…

We propose a new approach for reconstructing the 3D spatial distribution of small dislocation loops (DLs) from 2D TEM micrographs. This method is demonstrated for small DLs in tungsten, formed by low-dose ion-implantation, that appear as…

Materials Science · Physics 2018-04-04 Hongbing Yu , Xiaoou Yi , Felix Hofmann

We propose and study numerically the implicit approximation in time of the Navier-Stokes equations by a Galerkin-collocation method in time combined with inf-sup stable finite element methods in space. The conceptual basis of the…

Numerical Analysis · Mathematics 2020-09-25 Mathias Anselmann , Markus Bause

Perturbation techniques can be used as an alternative to supercomputer calculations in calculating gravitational radiation emitted by colliding black holes, provided the process starts with the black holes close to each other. We give a…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Hans-Peter Nollert , John Baker , Richard Price , Jorge Pullin

We construct initial data corresponding to a single perturbed Kerr black hole in vacuum. These data are defined on specific hyperboloidal ("ACMC-") slices on which the mean extrinsic curvature K asymptotically approaches a constant at…

General Relativity and Quantum Cosmology · Physics 2014-08-27 David Schinkel , Marcus Ansorg , Rodrigo Panosso Macedo

We have developed a new numerical code to study the evolution of distorted, rotating black holes. We discuss the numerical methods and gauge conditions we developed to evolve such spacetimes. The code has been put through a series of tests,…

General Relativity and Quantum Cosmology · Physics 2009-10-22 Steven R. Brandt , Edward Seidel

This work consists of two distinct parts. In the first part we present a new method for solving the initial value problem of general relativity. Given any spatial metric with a surface orthogonal Killing field and two freely specified…

General Relativity and Quantum Cosmology · Physics 2009-10-31 John Baker , Raymond Stanley Puzio

Gravitational perturbations about a Kerr black hole in the Newman-Penrose formalism are concisely described by the Teukolsky equation. New numerical methods for studying the evolution of such perturbations require not only the construction…

General Relativity and Quantum Cosmology · Physics 2009-10-30 Manuela Campanelli , Carlos O. Lousto

We present a non-perturbative method for calculating the abundance of primordial black holes given an arbitrary one-point probability distribution function for the primordial curvature perturbation, $P(\zeta)$. A non-perturbative method is…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-01 Andrew D. Gow , Hooshyar Assadullahi , Joseph H. P. Jackson , Kazuya Koyama , Vincent Vennin , David Wands

We follow the strategy initiated in Ref. [1] and proceed with the implementation of the Galerkin-Collocation domain decomposition (GCDD) applied to the dynamics of a spherical self-gravitating scalar field with the field equation in the…

General Relativity and Quantum Cosmology · Physics 2021-10-22 M. A. Alcoforado , R. F. Aranha , W. O. Barreto , H. P. de Oliveira

We propose an discontinuous Galerkin local orthogonal decomposition multiscale method for convection-diffusion problems with rough, heterogeneous, and highly varying coefficients. The properties of the multiscale method and the…

Numerical Analysis · Mathematics 2015-09-14 Daniel Elfverson

We propose energy-conserving discontinuous Galerkin (DG) methods for symmetric linear hyperbolic systems on general unstructured meshes. Optimal a priori error estimates of order $k+1$ are obtained for the semi-discrete scheme in one…

Numerical Analysis · Mathematics 2019-06-26 Guosheng Fu , Chi-Wang Shu