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Context: The solution of the nonlocal thermodynamical equilibrium (non-LTE) radiative transfer equation usually relies on stationary iterative methods, which may falsely converge in some cases. Furthermore, these methods are often unable to…

Solar and Stellar Astrophysics · Physics 2015-07-29 Julien Lambert , Eric Josselin , Nils Ryde , Alexandre Faure

We describe a numerical code to solve the equations for ideal magnetohydrodynamics (MHD). It is based on an explicit finite difference scheme on an Eulerian grid, called the Total Variation Diminishing (TVD) scheme, which is a…

Astrophysics · Physics 2009-10-22 Dongsu Ryu , T. W. Jones

We consider the flow of a Newtonian fluid in a three-dimensional domain, rotating about a vertical axis and driven by a vertically invariant horizontal body-force. This system admits vertically invariant solutions that satisfy the 2D…

Fluid Dynamics · Physics 2023-07-19 Basile Gallet

We present results of the application of the anisotropic hydrodynamics (aHydro) framework to (2+1)-dimensional boost invariant systems. The necessary aHydro dynamical equations are derived by taking moments of the Boltzmann equation using a…

Nuclear Theory · Physics 2012-06-20 Mauricio Martinez , Radoslaw Ryblewski , Michael Strickland

We have performed a 2.5 dimensional magnetohydrodynamic simulation that resolves the propagation and dissipation of Alfven waves in the solar atmosphere. Alfvenic fluctuations are introduced on the bottom boundary of the extremely large…

Solar and Stellar Astrophysics · Physics 2015-06-18 Takuma Matsumoto , Takeru K. Suzuki

With the use of our JOANNA code, which solves radiative equations for ion + electron and neutral fluids, we perform realistic 2.5D numerical simulations of plasma outflows associated with the solar granulation. These outflows exhibit…

Solar and Stellar Astrophysics · Physics 2019-11-06 D. Wójcik , B. Kuźma , K. Murawski , A. K. Srivastava

We consider the compressible barotropic Navier-Stokes equations in a half-line and study the time-asymptotic behavior toward the outgoing viscous shock wave. Precisely, we consider the two boundary problems: impermeable wall and inflow…

Analysis of PDEs · Mathematics 2025-01-08 Xushan Huang , Moon-Jin Kang , Jeongho Kim , Hobin Lee

We present results from direct numerical simulations of the Boussinesq equations in the presence of rotation and/or stratification, both in the vertical direction. The runs are forced isotropically and randomly at small scales and have…

Fluid Dynamics · Physics 2015-06-22 R. Marino , P. D. Mininni , D. L. Rosenberg , A. Pouquet

Steady state simulations} of magnetized electron fluid equations with strong anisotropic diffusion based on the first-order hyperbolic approach is carried out using cell-centered higher order upwind schemes, linear and weighted essentially…

Computational Physics · Physics 2019-03-14 Amareshwara Sainadh Chamarthi , Kimiya Komurasaki , Rei Kawashima

To unlock access to stronger winds, the offshore wind industry is advancing towards significantly larger and taller wind turbines. This massive upscaling motivates a departure from wind forecasting methods that traditionally focused on a…

Machine Learning · Computer Science 2025-11-18 Feng Ye , Xinxi Zhang , Michael Stein , Ahmed Aziz Ezzat

The evolution of the non-thermal emission emitted by pulsar wind nebulae is generally calculated using spatially-independent particle transport models. Although useful, these models implicitly assume that the source of non-thermal particles…

High Energy Astrophysical Phenomena · Physics 2013-08-09 Michael Vorster , Harm Moraal

Numerical simulation of compressible fluid flows is performed using the Euler equations. They include the scalar advection equation for the density, the vector advection equation for the velocity and a given pressure dependence on the…

Computational Engineering, Finance, and Science · Computer Science 2018-01-22 Petr N. Vabishchevich

We describe computational tools that have been developed to simulate dynamical mass transfer in semi-detached, polytropic binaries that are initially executing synchronous rotation upon circular orbits. Initial equilibrium models are…

Astrophysics · Physics 2009-11-06 Patrick M Motl , Joel E Tohline , Juhan Frank

Massive stars present strong stellar that which are described by the radiation driven wind theory. Accurate mass-loss rates are necessary to properly describe the stellar evolution across the Hertzsprung--Russel Diagram. We present a…

Solar and Stellar Astrophysics · Physics 2019-03-20 Alex C. Gormaz-Matamala , Michel Curé , Lydia S. Cidale , Roberto O. J. Venero

Flow of viscous fluids are not usually discussed in detail in general and basic courses of physics. This is due in part to the fact that the Navier-Stokes equation has analytical solution only for a few restricted cases, while more…

Physics Education · Physics 2015-12-08 Paulo Victor Santos Souza , Paulo Murilo Castro de Oliveira

Many traditional methods for wind turbine design and analysis assume quasi-steady aerodynamics, but atmospheric flows are inherently unsteady and modern turbine blades are susceptible to aeroelastic deformations. This study therefore…

Fluid Dynamics · Physics 2024-06-18 Nathaniel J. Wei , Omkar B. Shende

The wind-driving mechanism of asymptotic giant branch (AGB) stars is commonly attributed to a two-step process: first, gas in the stellar atmosphere is levitated by shockwaves caused by stellar pulsation, then accelerated outwards by…

Solar and Stellar Astrophysics · Physics 2018-11-07 S. Liljegren , S. Höfner , B. Freytag , S. Bladh

We present a 3D dynamical model of the orbital induced curvature of the wind-wind collision region in binary star systems. Momentum balance equations are used to determine the position and shape of the contact discontinuity between the…

Astrophysics · Physics 2009-11-13 E. R. Parkin , J. M. Pittard

This paper provides a methodology of verified computing for solutions to 1-dimensional advection equations with variable coefficients. The advection equation is typical partial differential equations (PDEs) of hyperbolic type. There are few…

Numerical Analysis · Mathematics 2019-07-03 Akitoshi Takayasu , Suro Yoon , Yasunori Endo

(abidged) Context: Stellar convection zones are characterized by vigorous high-Reynolds number turbulence at low Prandtl numbers. Aims: We study the dynamo and differential rotation regimes at varying levels of viscous, thermal, and…

Solar and Stellar Astrophysics · Physics 2017-02-22 P. J. Käpylä , M. J. Käpylä , N. Olspert , J. Warnecke , A. Brandenburg