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During the past decades the study of strongly interacting fluids experienced a tremendous progress. In the relativistic heavy ion accelerators, specially the RHIC and LHC colliders, it became possible to study not only fluids made of…

Nuclear Theory · Physics 2013-09-09 D. A. Fogaça , F. S. Navarra , L. G. Ferreira Filho

We introduce an innovative wavelet-based approach to dynamically adjust the local grid resolution to maintain a uniform specified error tolerance. Extending the work of Dubos and Kevlahan (2013), a wavelet multi-scale approximation is used…

Geophysics · Physics 2015-10-28 Matthias Aechtner , Nicholas Kevlahan , Thomas Dubos

We present an open-source Matlab framework, titled iFluid, for simulating the dynamics of integrable models using the theory of generalized hydrodynamics (GHD). The framework provides an intuitive interface, enabling users to define and…

Statistical Mechanics · Physics 2020-03-18 Frederik S. Møller , Jörg Schmiedmayer

This article is concerned with rigorously justifying the hydrostatic limit for continuously stratified incompressible fluids under the influence of gravity. The main distinction of this work compared to previous studies is the absence of…

Analysis of PDEs · Mathematics 2025-01-06 Vincent Duchêne , Roberta Bianchini

We analyze the mixed frame equations of radiation hydrodynamics under the approximations of flux-limited diffusion and a thermal radiation field, and derive the minimal set of evolution equations that includes all terms that are of leading…

Astrophysics · Physics 2009-11-11 Mark R. Krumholz , Richard I. Klein , Christopher F. McKee , John Bolstad

Our contribution concerns with the numerical solution of the 3D general relativistic hydrodynamical system of equations within the framework of the 3+1 formalism. We summarize the theoretical ingredients which are necessary in order to…

Astrophysics · Physics 2007-05-23 J. M. Ibanez , M. A. Aloy , J. A. Font , J. M. Marti , J. A. Miralles , J. A. Pons

We present a unified causal general relativistic formulation of dissipative and non-dissipative continuum mechanics. The presented theory is the first general relativistic theory that can deal simultaneously with viscous fluids as well as…

General Relativity and Quantum Cosmology · Physics 2019-10-08 Ilya Peshkov , Evgeniy Romenski , Francesco Fambri , Michael Dumbser

Simulating deep solar convection and its coupled mean-field motions is a formidable challenge where few observational results constrain models that suffer from the non-physical influence of the grid resolution. We present hydrodynamic…

Solar and Stellar Astrophysics · Physics 2022-12-07 G. Guerrero , A. M. Stejko , A. G. Kosovichev , P. K Smolarkiewicz , A. Strugarek

This talk gives an overview of the recently-formulated Fluid/Gravity correspondence, which was developed in the context of gauge/gravity duality. Mathematically, it posits that Einstein's equations (with negative cosmological constant) in…

General Relativity and Quantum Cosmology · Physics 2011-07-19 Veronika E. Hubeny

We report on a new capability added to our general relativistic radiation-magnetohydrodynamics code, Cosmos++: an implicit Monte Carlo (IMC) treatment for radiation transport. The method is based on a Fleck-type implicit discretization of…

Instrumentation and Methods for Astrophysics · Physics 2022-07-27 Nathaniel Roth , Peter Anninos , Peter B. Robinson , J. Luc Peterson , Brooke Polak , Tymothy K. Mangan , Kyle Beyer

Stochastic Gradient Langevin Dynamics (SGLD) is a popular variant of Stochastic Gradient Descent, where properly scaled isotropic Gaussian noise is added to an unbiased estimate of the gradient at each iteration. This modest change allows…

Machine Learning · Computer Science 2017-06-06 Maxim Raginsky , Alexander Rakhlin , Matus Telgarsky

The characteristic decomposition for GRMHD in the comoving frame of the fluid has been known for a long time. However, it has not been known in the coordinate frame of the simulation and in terms of the conserved variables evolved in…

General Relativity and Quantum Cosmology · Physics 2025-11-19 Saul A. Teukolsky

We present the extension of the differentiable hydrodynamics code, diffhydro, enabling scalable PDE-constrained inference and integrated hybrid physics-ML models for a wide range of astrophysical applications. New physics additions include…

Instrumentation and Methods for Astrophysics · Physics 2025-12-16 Benjamin Horowitz , Zarija Lukić , Kentaro Nagamine , Yuri Oku

Relativistic non-ideal fluid dynamics is formulated in 3+1 space--time dimensions. The equations governing dissipative relativistic hydrodynamics are given in terms of the time and the 3-space quantities which correspond to those familiar…

Nuclear Theory · Physics 2008-11-26 Azwinndini Muronga

We present a hydrodynamical description of spherical void evolution in modified gravity (MG), extending the standard General Relativity (GR) and dynamical dark energy treatment by encoding gravity modifications into effective couplings that…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-20 Tommaso Moretti , Noemi Frusciante , Giovanni Verza , Francesco Pace

We present a numerical code for radiation hydrodynamics designed as a module for the freely available PLUTO code. We adopt a gray approximation and include radiative transfer following a two-moment approach by imposing the M1 closure to the…

Earth and Planetary Astrophysics · Physics 2021-01-20 Julio David Melon Fuksman , Hubert Klahr , Mario Flock , Andrea Mignone

Axisymmetric numerical simulations of rotating stellar core collapse to a neutron star are performed in the framework of full general relativity. The so-called Cartoon method, in which the Einstein field equations are solved in the…

General Relativity and Quantum Cosmology · Physics 2011-07-18 Masaru Shibata , Yu-ichirou Sekiguchi

We propose and analyze a new method for the unsteady incompressible magnetohydrodynamics equations on convex domains with hybrid approximations of both vector-valued and scalar-valued fields. The proposed method is convection-semirobust,…

Numerical Analysis · Mathematics 2026-02-11 Daniele A. Di Pietro , Jerome Droniou , Vito Patierno

We present a co-scaling grid formalism and its implementation in the magnetohydrodynamics code Athena++. The formalism relies on flow symmetries in astrophysical problems involving expansion, contraction, and center-of-mass motion. The grid…

Instrumentation and Methods for Astrophysics · Physics 2021-10-13 Roark Habegger , Fabian Heitsch

We have developed an adaptive multigrid code for solving the Poisson equation in gravitational simulations. Finer rectangular subgrids are adaptively created in locations where the density exceeds a local level-dependent threshold. We…

Astrophysics · Physics 2015-06-24 I. Suisalu , E. Saar