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Modern astrophysical simulations aim to accurately model an ever-growing array of physical processes, including the interaction of fluids with magnetic fields, under increasingly stringent performance and scalability requirements driven by…

Instrumentation and Methods for Astrophysics · Physics 2019-02-08 Thomas Guillet , Rüdiger Pakmor , Volker Springel , Praveen Chandrashekar , Christian Klingenberg

In this paper we develop the new semi-analitical model of a tidally perturbed or tidally disrupted star proposed recently by two of us. This model is effectively a one dimensional Lagrangian model and it can be evolved numerically much…

Astrophysics · Physics 2009-11-07 P. B. Ivanov , M. A. Chernyakova , I. D. Novikov

This work is concerned with the analysis of a space-time finite element discontinuous Galerkin method on polytopal meshes (XT-PolydG) for the numerical discretization of wave propagation in coupled poroelastic-elastic media. The…

Numerical Analysis · Mathematics 2023-12-05 Paola F. Antonietti , Michele Botti , Ilario Mazzieri

We present a code for solving the coupled Einstein-hydrodynamics equations to evolve relativistic, self-gravitating fluids. The Einstein field equations are solved in generalized harmonic coordinates on one grid using pseudospectral…

General Relativity and Quantum Cosmology · Physics 2008-12-18 Matthew D. Duez , Francois Foucart , Lawrence E. Kidder , Harald P. Pfeiffer , Mark A. Scheel , Saul A. Teukolsky

The paper develops high order accurate Runge-Kutta discontinuous local evolution Galerkin (RKDLEG) methods on the cubed-sphere grid for the shallow water equations (SWEs). Instead of using the dimensional splitting method or solving…

Numerical Analysis · Mathematics 2017-09-20 Yangyu Kuang , Kailiang Wu , Huazhong Tang

Hydrodynamical numerical methods that converge with high-order hold particular promise for astrophysical studies, as they can in principle reach prescribed accuracy goals with higher computational efficiency than standard second- or…

Instrumentation and Methods for Astrophysics · Physics 2023-05-05 Miha Cernetic , Volker Springel , Thomas Guillet , Rüdiger Pakmor

We generalize the energy-based discontinuous Galerkin method proposed in [SIAM J. Num. Anal., 53(6):2705-2726, 2015.] to second-order semilinear wave equations. A stability and convergence analysis is presented along with numerical…

Numerical Analysis · Mathematics 2020-07-15 Daniel Appelo , Thomas Hagstrom , Qi Wang , Lu Zhang

We develop and analyse a numerical method for the time-fractional nonlocal thermistor problem. By rigorous proofs, some error estimates in different contexts are derived, showing that the combination of the backward differentiation in time…

Analysis of PDEs · Mathematics 2017-03-17 Moulay Rchid Sidi Ammi , Delfim F. M. Torres

Element Method. The Finite Volume Method guarantees local and global mass conservation. A property not satisfied by the Finite Volume Method. On the down side, the Finite Volume Method requires non trivial modifications to attain high order…

Numerical Analysis · Mathematics 2022-01-12 Danalie Azofeifa , Miguel Angel Moreles , Federico Angel Velazquez-Muñoz

A dispersive wave hydro-morphodynamic model coupling the Green-Naghdi equations (the hydrodynamic part) with the sediment continuity Exner equation (the morphodynamic part) is presented. Numerical solution algorithms based on discontinuous…

Numerical Analysis · Mathematics 2021-02-03 Kazbek Kazhyken , Juha Videman , Clint Dawson

We discuss the development, verification, and performance of a GPU accelerated discontinuous Galerkin method for the solutions of two dimensional nonlinear shallow water equations. The shallow water equations are hyperbolic partial…

Numerical Analysis · Mathematics 2023-07-19 R Gandham , D S Medina , T Warburton

We study the evolution of magnetized and rigidly rotating neutron stars within a fully general relativistic implementation of ideal magnetohydrodynamics with no assumed symmetries in three spatial dimensions. The stars are modeled as…

General Relativity and Quantum Cosmology · Physics 2010-08-24 Steven L. Liebling , Luis Lehner , David Neilsen , Carlos Palenzuela

We design an arbitrary high-order accurate nodal discontinuous Galerkin spectral element approximation for the nonlinear two dimensional shallow water equations with non-constant, possibly discontinuous, bathymetry on unstructured, possibly…

Numerical Analysis · Mathematics 2016-06-23 Niklas Wintermeyer , Andrew R. Winters , Gregor J. Gassner , David A. Kopriva

We devise a space-time tensor method for the low-rank approximation of linear parabolic evolution equations. The proposed method is a stable Galerkin method, uniformly in the discretization parameters, based on a Minimal Residual…

Numerical Analysis · Mathematics 2019-09-11 Thomas Boiveau , Virginie Ehrlacher , Alexandre Ern , Anthony Nouy

We present our first successful numerical results of 3D general relativistic simulations in which the Einstein equation as well as the hydrodynamic equations are fully solved. This paper is especially devoted to simulations of test problems…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Masaru Shibata

We introduce a Lagrangian nodal discontinuous Galerkin (DG) cell-centered hydrodynamics method for solving multi-dimensional hyperbolic systems. By incorporating an adaptation of Zalesak's flux-corrected transport algorithm, we combine a…

Numerical Analysis · Mathematics 2025-10-30 Joshua Vedral , Nathaniel Morgan , Dmitri Kuzmin , Jacob Moore

We present a new $hp$-version space-time discontinuous Galerkin (dG) finite element method for the numerical approximation of parabolic evolution equations on general spatial meshes consisting of polygonal/polyhedral (polytopic) elements,…

Numerical Analysis · Mathematics 2024-11-07 Andrea Cangiani , Zhaonan Dong , Emmanuil H. Georgoulis

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

General-relativistic equilibria of differentially rotating stars are expected in a number of astrophysical scenarios, from core-collapse supernovae to the remnant of binary neutron-star mergers. The latter, in particular, have been the…

General Relativity and Quantum Cosmology · Physics 2024-06-18 Marie Cassing , Luciano Rezzolla

We present and analyse a space-time discontinuous Galerkin method for wave propagation problems. The special feature of the scheme is that it is a Trefftz method, namely that trial and test functions are solution of the partial differential…

Numerical Analysis · Mathematics 2022-08-26 Fritz Kretzschmar , Andrea Moiola , Ilaria Perugia , Sascha M. Schnepp