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In this paper we present results from a series of hydrodynamical tests aimed at validating the performance of a smoothed particle hydrodynamics (SPH) formulation in which gradients are derived from an integral approach. We specifically…

Instrumentation and Methods for Astrophysics · Physics 2016-11-09 R. Valdarnini

This paper presents a new resolution strategy for multi-scale streamer discharge simulations based on a second order time adaptive integration and space adaptive multiresolution. A classical fluid model is used to describe plasma…

Numerical Analysis · Mathematics 2012-04-10 Max Duarte , Zdenek Bonaventura , Marc Massot , Anne Bourdon , Stéphane Descombes , Thierry Dumont

We present a six-moment multi-fluid model, which solves the governing equations for both ions and electrons, with pressure anisotropy along and perpendicular to the magnetic field direction, as well as the complete set of Maxwell equations.…

Computational Physics · Physics 2019-05-01 Zhenguang Huang , Gabor Toth , Bart van der Holst , Yuxi Chen , Tamas Gombosi

The quasi-neutral hybrid model with kinetic ions and fluid electrons is a promising approach for bridging the inherent multi-scale nature of many problems in space and laboratory plasmas. Here, a novel, implicit, particle-in-cell based…

Plasma Physics · Physics 2018-11-14 A. Stanier , L. Chacón , G. Chen

A numerical scheme is proposed for the solution of the three-dimensional radiative transfer equation with variable optical depth. We show that time-dependent ray tracing is an attractive choice for simulations of astrophysical ionization…

Astrophysics · Physics 2009-10-31 Alexei Razoumov , Douglas Scott

Axisymmetric magnetohydrodynamics (MHD) can be invoked for describing astrophysical magnetized flows and formulated to model stellar magnetospheres including main sequence stars (e.g. the Sun), compact stellar objects [e.g. magnetic white…

Solar and Stellar Astrophysics · Physics 2014-03-05 Lile Wang , Yu-Qing Lou

In this paper, continuous research is undertaken to explore the underlying mechanism of numerical shock instabilities of Godunov-type schemes for strong shocks. By conducting dissipation analysis of Godunov-type schemes and a sequence of…

Computational Physics · Physics 2021-01-26 Wenjia Xie , Zhengyu Tian , Ye Zhang , Hang Yu , Fan Yang

In this paper we consider the Benjamin equation, a partial differential equation that models one-way propagation of long internal waves of small amplitude along the interface of two fluid layers under the effects of gravity and surface…

Numerical Analysis · Mathematics 2014-05-23 V. A. Dougalis , A. Duran , D. Mitsotakis

Aims. The goal of the paper is to present a detailed study of the propagation of low velocity (5 to 25 km s-1) stationary molecular shocks in environments illuminated by an external ultraviolet (UV) radiation field. In particular, we intend…

We describe a new numerical scheme for MHD which combines a higher order Godunov method (PPM) with Constrained Transport. The results from a selection of multidimensional test problems are presented. The complete test suite used to validate…

Astrophysics · Physics 2009-11-10 James M. Stone , Thomas A. Gardiner

Multi-scale wave propagation problems are computationally costly to solve by traditional techniques because the smallest scales must be represented over a domain determined by the largest scales of the problem. We have developed and…

Numerical Analysis · Mathematics 2009-11-16 Bjorn Engquist , Henrik Holst , Olof Runborg

A cosmological multidimensional hydrodynamic code is described and tested. This code is based on modern high-resolution shock-capturing techniques. It can make use of a linear or a parabolic cell reconstruction as well as an approximate…

Astrophysics · Physics 2016-08-15 Vicent Quilis , Jose Ma. Ibanez , Diego Saez

Continuing on our previous work [ArXiv:1212.2644], we develop semi-implicit numerical methods for solving low Mach number fluctuating hydrodynamic equations appropriate for modeling diffusive mixing in isothermal mixtures of fluids with…

Numerical Analysis · Mathematics 2016-01-20 A. J. Nonaka , Y. Sun , J. B. Bell , A. Donev

When modeling astrophysical fluid flows, it is often appropriate to discard the canonical magnetohydrodynamic approximation thereby freeing the magnetic field to diffuse with respect to the bulk velocity field. As a consequence, however,…

Astrophysics · Physics 2009-11-13 Stephen O'Sullivan , Turlough P. Downes

I consider the nonaxisymmetric linear theory of a rotating, isothermal magnetohydrodynamic (MHD) shear flow. The analysis is performed in the shearing box, a local model of a thin disk, using a decomposition in terms of shearing waves,…

Astrophysics · Physics 2011-02-11 Bryan M. Johnson

From a mathematical perspective, radiation hydrodynamics can be thought of as a system of hyperbolic balance laws with dual multiscale behavior (multiscale behavior associated with the hyperbolic wave speeds as well as multiscale behavior…

Computational Physics · Physics 2015-05-19 Michael D Sekora , James M Stone

In this work we present a proof of concept of CUDA-capable, resistive, multi-fluid models of relativistic magnetohydrodynamics (RMHD). Resistive and multi-fluid codes for simulating models of RMHD suffer from stiff source terms, so it is…

Computational Physics · Physics 2019-01-16 Alex James Wright , Ian Hawke

We consider the Riemann problem of the dilute approximation equations with spatiotemporally dependent volume fractions from the full model of suspension, in which the particles settle to the solid substrate and the clear liquid film flows…

Analysis of PDEs · Mathematics 2017-09-05 Kaname Matsue , Kyoko Tomoeda

We describe how analytic solutions for linear hydromagnetic waves can be used for testing cosmological magnetohydrodynamic (MHD) codes. We start from the comoving MHD equations and derive analytic solutions for the amplitude evolution of…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-03 Thomas Berlok

Gravity-driven flows of liquid films are frequent in nature and industry, such as in landslides, lava flow, cooling of nuclear reactors, and coating processes. In many of these cases, the liquid is non-Newtonian and has particular…

Fluid Dynamics · Physics 2023-11-21 Bruno Pelisson Chimetta , Erick de Moraes Franklin