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The current status of numerical solutions for the equations of ideal general relativistic hydrodynamics is reviewed. With respect to an earlier version of the article the present update provides additional information on numerical schemes…

General Relativity and Quantum Cosmology · Physics 2016-10-19 Jose A. Font

We present a more accurate numerical scheme for the calculation of diffusive shock acceleration of cosmic rays using Stochastic Differential Equations. The accuracy of this scheme is demonstrated using a simple analytical flow profile that…

High Energy Astrophysical Phenomena · Physics 2011-03-17 A. Achterberg , K. M. Schure

In this paper, a second-order generalized Riemann problem (GRP) solver is developed for a two-layer thin film model. Extending the first-order Godunov approach, the solver is used to construct a temporal-spatial coupled second-order…

Numerical Analysis · Mathematics 2025-05-27 Rahul Barthwal , Christian Rohde , Yue Wang

Cosmic ray (CR) transport and acceleration is determined by the properties of magnetic turbulence. Recent advances in MHD turbulence call for revisions in the paradigm of cosmic ray transport. We use the models of magnetohydrodynamic…

High Energy Astrophysical Phenomena · Physics 2015-06-15 Huirong Yan

Radiation flow through an inhomogeneous medium is critical in a wide range of physics and astronomy applications from transport across cloud layers on the earth to the propagation of supernova blast-waves producing UV and X-ray emission in…

Accurate simulations of flows in stellar interiors are crucial to improving our understanding of stellar structure and evolution. Because the typically slow flows are merely tiny perturbations on top of a close balance between gravity and…

Solar and Stellar Astrophysics · Physics 2021-08-18 P. V. F. Edelmann , L. Horst , J. P. Berberich , R. Andrassy , J. Higl , G. Leidi , C. Klingenberg , F. K. Roepke

We assess the validity of a single step Godunov scheme for the solution of the magneto-hydrodynamics equations in more than one dimension. The scheme is second-order accurate and the temporal discretization is based on the dimensionally…

Instrumentation and Methods for Astrophysics · Physics 2014-11-20 A. Mignone , P. Tzeferacos

This paper collects the efforts done in our previous works [P. Degond, S. Jin, L. Mieussens, A Smooth Transition Between Kinetic and Hydrodynamic Equations, J. Comp. Phys., 209 (2005) 665--694.],[P.Degond, G. Dimarco, L. Mieussens, A Moving…

Mathematical Physics · Physics 2014-04-08 Pierre Degond , Giacomo Dimarco , Luc Mieussens

This paper enhances the Diffuse Interface Method (DIM) for simulating compressible multiphase flows across all Mach numbers by addressing the accuracy challenges posed at low Mach regimes. A correction to the Riemann solver is introduced,…

Numerical Analysis · Mathematics 2025-03-17 Ghanshyam Bharate , J. C. Mandal

An algorithm for simulating self-gravitating cosmological astrophysical fluids is presented. The advantages include a large dynamic range, parallelizability, high resolution per grid element and fast execution speed. The code is based on a…

Astrophysics · Physics 2009-10-30 Ue-Li Pen

A generalization of the random fluid hydrodynamic fluctuation theory due to Landau and Lifshitz is applied to describe cosmological fluctuations in systems with radiation and scalar fields. The viscous pressures, parametrized in terms of…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-14 Mar Bastero-Gil , Arjun Berera , Ian G. Moss , Rudnei O. Ramos

We consider a sharp-interface approach for the inviscid isothermal dynamics of compressible two-phase flow, that accounts for phase transition and surface tension effects. To fix the mass exchange and entropy dissipation rate across the…

Fluid Dynamics · Physics 2016-11-10 Christian Rohde , Christoph Zeiler

We investigate numerically the contribution to the cosmic gamma-ray background from cosmic-rays ions and electrons accelerated at intergalactic shocks associated with cosmological structure formation. We show that the kinetic energy of…

Astrophysics · Physics 2008-11-26 Francesco Miniati

Cosmological simulations are powerful tools in the context of structure formation. They allow us to explore the assembly and clustering of dark matter halos, to validate or reject possible scenarios of structure formation, and to…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-12 Milena Valentini , Klaus Dolag

A novel description of kinetic theory dynamics is proposed in terms of resummed moments that embed information of both hydrodynamic and non-hydrodynamic modes. The resulting expansion can be used to extend hydrodynamics to higher orders in…

Nuclear Theory · Physics 2019-01-16 L. Tinti , G. Vujanovic , J. Noronha , U. Heinz

The interaction of a shock wave with a bubble features in many engineering and emerging technological applications, and has been used widely to test new numerical methods for compressible interfacial flows. Recently, density-based…

Computational Physics · Physics 2019-07-04 Fabian Denner , Berend van Wachem

While exact and approximate Riemann solvers are widely used, they exhibit two fundamental limitations: 1) Fail to represent continuous entropy transport processes, resulting in thermodynamic incompatibility that limits their applicability…

Numerical Analysis · Mathematics 2026-01-26 Zhixin Huo

We derive a consistent set of moments equations for CR-magnetohydrodynamics, assuming a gyrotropic distribution function (DF). Unlike previous efforts we derive a closure, akin to the M1 closure in radiation hydrodynamics (RHD), that is…

High Energy Astrophysical Phenomena · Physics 2022-03-18 Philip F. Hopkins , Jonathan Squire , Iryna S. Butsky

During the past decades, the numerical methods based on Navier-Stokes (N-S) equations and direct simulation Monte Carlo (DSMC) methods have been proved effective in simulating flows in the continuum and rarefied regimes, respectively.…

Fluid Dynamics · Physics 2024-09-24 Sirui Yang , Sha Liu , Junzhe Cao , Chengwen Zhong

We present a parameter study of the magnetohydrodynamical dynamo driven by cosmic rays in the interstellar medium (ISM) focusing on the efficiency of magnetic field amplification and the issue of energy equipartition between magnetic,…

Astrophysics · Physics 2015-05-13 Michał Hanasz , Katarzyna Otmianowska-Mazur , Grzegorz Kowal , Harald Lesch