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A general method for constructing high order upwind schemes for multidimensional magnetohydrodynamics (MHD), having as a main built-in condition the divergence-free constraint $\divb=0$ for the magnetic field vector $\bb$, is proposed. The…

Astrophysics · Physics 2009-10-31 P. Londrillo , L. Del Zanna

Fluid discontinuities, such as shock fronts and vortex sheets, can reflect waves and become unstable to corrugation. Analytical calculations of these phenomena are tractable in the simplest cases only, while their numerical simulations are…

Plasma Physics · Physics 2023-08-16 William Béthune

Equations of ideal magnetohydrodynamics (MHD) play an important role in the studies of turbulence, astrophysics, and plasma physics. These equations possess remarkable geometric structures and symmetries. Indeed, they admit a geodesic…

Mathematical Physics · Physics 2026-03-19 Michael Roop

We present a novel method for guaranteeing linear momentum in learned physics simulations. Unlike existing methods, we enforce conservation of momentum with a hard constraint, which we realize via antisymmetrical continuous convolutional…

Machine Learning · Computer Science 2022-11-03 Lukas Prantl , Benjamin Ummenhofer , Vladlen Koltun , Nils Thuerey

A physically consistent approach is considered for defining an external magnetic field as needed in computational fluid dynamics problems involving magnetohydrodynamics (MHD). The approach results in simple analytical formulae that can be…

Fluid Dynamics · Physics 2009-11-25 E. V. Votyakov , S. C. Kassinos , X. Albets-Chico

We present a new approach to Eulerian computational fluid dynamics that is designed to work at high Mach numbers encountered in astrophysical hydrodynamic simulations. The Eulerian fluid conservation equations are solved in an adaptive…

Astrophysics · Physics 2009-11-10 Hy Trac , Ue-Li Pen

The Athena MHD code has been extended to integrates the motion of particles coupled with the gas via aerodynamic drag, in order to study the dynamics of gas and solids in protoplanetary disks and the formation of planetesimals. Our…

Earth and Planetary Astrophysics · Physics 2015-05-19 Xue-Ning Bai , James M. Stone

Fluctuating hydrodynamics based techniques have been developed in recent years for the simulation of Brownian motion of particles. These mesoscale simulation tools are viable approaches for problems where molecular dynamics simulations may…

Fluid Dynamics · Physics 2014-02-11 Yong Chen , Neelesh A. Patankar

Obtaining a stable magnetohydrodynamical (MHD) formalism in SPH - i.e. smoothed particle magnetohydrodynamics (SPMHD) - has proven remarkably difficult. To implement MHD requires two steps: a modification to the momentum equation and an…

Instrumentation and Methods for Astrophysics · Physics 2016-06-23 Benjamin T. Lewis , Matthew R. Bate , Terrence S. Tricco

In this work, we present a positivity-preserving adaptive filtering approach for discontinuous spectral element approximations of the ideal magnetohydrodynamics equations. This approach combines the entropy filtering method (Dzanic and…

Numerical Analysis · Mathematics 2023-09-19 Tarik Dzanic , Freddie D. Witherden

Lagrangian particle-based methods have opened new perspectives for the investigation of complex problems with large free-surface deformation. Some well-known particle-based methods adopted to solve non-linear hydrodynamics problems are the…

Fluid Dynamics · Physics 2023-06-06 Rubens Augusto Amaro Junior , Liang-Yee Cheng , Sergei K. Buruchenko

Lagrangian reduction by stages is used to derive the Euler-Poincar\'e equations for the nondissipative coupled motion and micromotion of complex fluids. We mainly treat perfect complex fluids (PCFs) whose order parameters are continuous…

Chaotic Dynamics · Physics 2007-05-23 Darryl D. Holm

A variational integrator for ideal magnetohydrodynamics is derived by applying a discrete action principle to a formal Lagrangian. Discrete exterior calculus is used for the discretisation of the field variables in order to preserve their…

Numerical Analysis · Mathematics 2018-03-13 Michael Kraus , Omar Maj

In this paper we discuss recent applications of the Smoothed Particle Hydrodynamics (SPH) method to the simulation of supersonic turbulence in the interstellar medium, as well as giving an update on recent algorithmic developments in…

Instrumentation and Methods for Astrophysics · Physics 2010-02-26 Daniel J. Price , Christoph Federrath

This paper establishes the global existence and uniqueness of smooth solutions to the two-dimensional compressible magnetohydrodynamic system when the initial data is close to an equilibrium state. In addition, explicit large-time decay…

Analysis of PDEs · Mathematics 2017-03-31 Jiahong Wu , Yifei Wu

We present an extension of the Piecewise Parabolic Method to special relativistic fluid dynamics in multidimensions. The scheme is conservative, dimensionally unsplit, and suitable for a general equation of state. Temporal evolution is…

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

We propose a new class of finite element approximations to ideal compressible magnetohydrodynamic equations in smooth regime. Following variational approximations developed for fluid models in the last decade, our discretizations are built…

Numerical Analysis · Mathematics 2024-02-29 Valentin Carlier , Martin Campos-Pinto

In this paper a simple, robust, and general purpose approach to implement the Incompressible Smoothed Particle Hydrodynamics (ISPH) method is proposed. This approach is well suited for implementation on CPUs and GPUs. The method is…

Numerical Analysis · Mathematics 2021-05-06 Abhinav Muta , Prabhu Ramachandran , Pawan Negi

The existence of global-in-time classical solutions to the Cauchy problem of incompressible Magnetohydrodynamic flows with zero magnetic diffusivity is considered in two dimensions. The linearization of equations is a degenerated…

Analysis of PDEs · Mathematics 2014-05-02 Xianpeng Hu , Fanghua Lin

We present and test a new, special-relativistic formulation of Smoothed Particle Hydrodynamics (SPH). Our approach benefits from several improvements with respect to earlier relativistic SPH formulations. It is self-consistently derived…

High Energy Astrophysical Phenomena · Physics 2015-05-13 S. Rosswog