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An approximate Riemann solver for the equations of relativistic magnetohydrodynamics (RMHD) is derived. The HLLC solver, originally developed by Toro, Spruce and Spears, generalizes the algorithm described in a previous paper (Mignone &…

Astrophysics · Physics 2009-11-11 A. Mignone , G. Bodo

We present \texttt{SACRA-2D}, a new MPI and OpenMP parallelized, fully relativistic hydrodynamics (GRHD) code in dynamical spacetime under axial symmetry with the cartoon method using the finite-volume shock-capturing schemes for…

High Energy Astrophysical Phenomena · Physics 2025-02-06 Alan Tsz-Lok Lam , Masaru Shibata

The detection of gravitational waves has opened a new era for astronomy, allowing for the combined use of gravitational wave and electromagnetic emissions to directly probe the physics of compact objects, still poorly understood. So far,…

General Relativity and Quantum Cosmology · Physics 2023-01-05 Alessandro Lupi

We study time evolution of sub-Keplerian transonic accretion flows onto black holes using a general relativistic numerical simulation code. We perform simulations around the black holes having non-zero rotation. We first compare…

High Energy Astrophysical Phenomena · Physics 2018-11-07 Jinho Kim , Sudip K. Garain , Sandip K. Chakrabarti , Dinshaw S. Balsara

A third order shock-capturing numerical scheme for three-dimensional special relativistic magnetohydrodynamics (3-D RMHD) is presented and validated against several numerical tests. The simple and efficient central scheme described in Paper…

Astrophysics · Physics 2009-11-07 L. Del Zanna , N. Bucciantini , P. Londrillo

We present a discontinuous Galerkin-finite-difference hybrid scheme that allows high-order shock capturing with the discontinuous Galerkin method for general relativistic magnetohydrodynamics. The hybrid method is conceptually quite simple.…

General Relativity and Quantum Cosmology · Physics 2024-01-17 Nils Deppe , François Hébert , Lawrence E. Kidder , Saul A. Teukolsky

The paper proposes a second-order accurate direct Eulerian generalized Riemann problem (GRP) scheme for the spherically symmetric general relativistic hydrodynamical (RHD) equations and a second-order accurate discretization for the…

Numerical Analysis · Mathematics 2016-07-29 Kailiang Wu , Huazhong Tang

In this paper, we propose a variant of Riemannian stochastic recursive gradient method that can achieve second-order convergence guarantee and escape saddle points using simple perturbation. The idea is to perturb the iterates when gradient…

Optimization and Control · Mathematics 2020-10-30 Andi Han , Junbin Gao

We describe a novel Godunov-type numerical method for solving the equations of resistive relativistic magnetohydrodynamics. In the proposed approach, the spatial components of both magnetic and electric fields are located at zone interfaces…

Computational Physics · Physics 2019-05-01 A. Mignone , G. Mattia , G. Bodo , L. Del Zanna

The shallow water equations are numerically solved to simulate free surface flows. The convective flux terms in the shallow water equations need to be discretized using a Riemann solver to capture shocks and discontinuity for certain flow…

Fluid Dynamics · Physics 2024-10-10 D. Satyaprasad , Soumendra Nath Kuiry , S. Sundar

We present authors' new theory of the RT-equations, nonlinear elliptic partial differential equations which determine the coordinate transformations which smooth connections $\Gamma$ to optimal regularity, one derivative smoother than the…

General Relativity and Quantum Cosmology · Physics 2020-11-10 Moritz Reintjes , Blake Temple

We present a new approach for stably evolving general relativistic magnetohydrodynamic (GRMHD) simulations in regions where the magnetization $\sigma=b^2/\rho c^2$ becomes large. GRMHD codes typically struggle to evolve plasma above…

High Energy Astrophysical Phenomena · Physics 2024-07-16 Andrew Chael

There is great interest in numerical relativity simulations involving matter due to the likelihood that binary compact objects involving neutron stars will be detected by gravitational wave observatories in the coming years, as well as to…

General Relativity and Quantum Cosmology · Physics 2012-06-06 William E. East , Frans Pretorius , Branson C. Stephens

The basic and fundamental aspects of General Relativity are in general analysed in mathematical level of coordinate basis or holonomic frame by several authors in the literature. However, for many purposes it is more convenient to use a…

General Relativity and Quantum Cosmology · Physics 2017-11-28 Wytler Cordeiro dos Santos

This paper looks at how changes of coordinates on a pseudo-Riemannian manifold induce homogeneous linear transformations on its tangent spaces. We see that a pseudo-orthonormal frame in a given tangent space is the basis for a set of…

General Physics · Physics 2022-11-15 Tom Lawrence

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 describe an implicit general relativistic hydrodynamics code. The evolution equations are formulated in comoving coordinates. A conservative finite differencing of the Einstein equations is outlined, and artificial viscosity and…

Astrophysics · Physics 2010-05-12 Matthias Liebendoerfer , Stephan Rosswog , Friedrich-Karl Thielemann

The Generalized Riemann Problems (GRP) for nonlinear hyperbolic systems of balance laws in one space dimension are now well-known and can be formulated as follows: Given initial-data which are smooth on two sides of a discontinuity,…

Numerical Analysis · Mathematics 2013-03-13 Jianzhen Qian , Jiequan Li , Shuanghu Wang

Boundary integral equations and Nystrom discretization provide a powerful tool for the solution of Laplace and Helmholtz boundary value problems. However, often a weakly-singular kernel arises, in which case specialized quadratures that…

Numerical Analysis · Mathematics 2012-11-22 S. Hao , A. H. Barnett , P. G. Martinsson , P. Young

The second paper of this series presents two robust entropy stable shock-capturing methods for discontinuous Galerkin spectral element (DGSEM) discretizations of the compressible magneto-hydrodynamics (MHD) equations. Specifically, we use…