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In this paper, Beltrami vector fields in several orthogonal coordinate systems are obtained analytically and numerically. Specifically, axisymmetric incompressible inviscid steady state Beltrami (Trkalian) fluid flows are obtained with the…

Fluid Dynamics · Physics 2020-01-01 Pavel Bělík , Xueqing Su , Douglas P. Dokken , Kurt Scholz , Mikhail M. Shvartsman

In the article the authors present a numerical method for modelling a laminar-turbulent transition in magnetohydrodynamic flows. The equations in the small magnetic Reynolds numbers approach is considered. Speed, pressure and electrical…

Fluid Dynamics · Physics 2019-11-29 Alexander V. Proskurin , Anatoly M. Sagalakov

High Mach number shocks are ubiquitous in interstellar turbulence. The Pencil Code is particularly well suited to the study of magnetohydrodynamics in weakly compressible turbulence and the numerical investigation of dynamos because of its…

Astrophysics of Galaxies · Physics 2020-01-15 Frederick A. Gent , Mordecai-Mark Mac Low , Maarit J. Käpylä , Graeme R. Sarson , James F. Hollins

(abridged) Pulsar activity and its related radiation mechanism are usually explained by invoking some plasma processes occurring inside the magnetosphere. Despite many detailed local investigations, the global electrodynamics around those…

High Energy Astrophysical Phenomena · Physics 2015-06-05 J. Pétri

We investigate static spherically symmetric perfect fluid models in Newtonian gravity for barotropic equations of state that are asymptotically polytropic at low and high pressures. This is done by casting the equations into a 3-dimensional…

Astrophysics · Physics 2009-11-07 J. Mark Heinzle , Claes Uggla

We discuss axisymmetric force-free pulsar magnetospheres with magnetically collimated jets and a disk-wind obtained by numerical solution of the pulsar equation. This solution represents an alternative to the quasi-spherical wind solutions…

Astrophysics · Physics 2008-11-26 Richard V. E. Lovelace , Leaf Turner , Marina M. Romanova

This paper presents numerical results in comparison with experimental data of nominally static aeroelastic polars of the second ASDMAD (Aero-Structural Dynamics Methods for Airplane Design) campaign conducted in the European Transonic…

This paper deals with a nonhomogeneous scalar parabolic equation with possibly degenerate diffusion term; the process has only one stationary state. The equation can be interpreted as modeling collective movements (crowd dynamics, for…

Analysis of PDEs · Mathematics 2017-02-17 Andrea Corli , Luisa Malaguti

We introduce a second-order numerical scheme for compressible atmospheric motions at small to planetary scales. The collocated finite volume method treats the advection of mass, momentum, and mass-weighted potential temperature in…

Numerical Analysis · Mathematics 2020-01-08 Tommaso Benacchio , Rupert Klein

A novel simulation framework has been developed in this study for the direct numerical simulation of the aerodynamic breakup of a vaporizing drop. The interfacial multiphase flow with phase change is resolved using a consistent geometric…

Fluid Dynamics · Physics 2023-05-10 Bradley Boyd , Yue Ling

We present two promising applications of training machine learning models inside a differentiable astrophysical (magneto)hydrodynamics simulator. First, we address the problem of slow convergence in hydrodynamical simulations of wind-blown…

Instrumentation and Methods for Astrophysics · Physics 2025-12-09 Leonard Storcks , Tobias Buck

We present the numerical simulations of winds from evolved giant stars using a fully non-linear, time dependent 2.5-dimensional magnetohydrodynamic (MHD) code. This study extends our previous fully non-linear MHD wind simulations to include…

Solar and Stellar Astrophysics · Physics 2015-05-19 Vladimir Airapetian , Kenneth G. Carpenter , Leon Ofman

We report on the development of an implicit multi-D hydrodynamic code for stellar evolution. We present two test-cases relevant for the first scientific goal of the code: the simulation of convection in pulsating stars. First results on a…

A combination of analytical and numerical techniques are used to efficiently determine the qualitative and quantitative behaviour of a one-basin zonally averaged thermohaline circulation ocean model. In contrast to earlier studies which use…

ao-sci · Physics 2018-07-25 G. A. Schmidt , L. A. Mysak

In this paper we propose a numerical method to solve a 2D advection-diffusion equation, in the highly oscillatory regime. We use an efficient and robust integrator which leads to an accurate approximation of the solution without any time…

Numerical Analysis · Mathematics 2023-07-27 Clarissa Astuto , Mohammed Lemou , Giovanni Russo

Our ability to predict the structure and evolution of stars is in part limited by complex, 3D hydrodynamic processes such as convective boundary mixing. Hydrodynamic simulations help us understand the dynamics of stellar convection and…

We model molecular outflows produced by the time dependent interaction between a stellar wind and a rotating cloud envelope in gravitational collapse, studied by Ulrich. We consider spherical and anisotropic stellar winds. We assume that…

Solar and Stellar Astrophysics · Physics 2019-07-10 J. A. López-Vázquez , J. Cantó , S. Lizano

We present numerical simulation of 2D turbulent flow using a new model for the subgrid scales which are computed using a dynamic equation linking the subgrid scales with the resolved velocity. This equation is not postulated, but derived…

Fluid Dynamics · Physics 2009-11-07 J. -P. Laval , B. Dubrulle , S. Nazarenko

In this paper, we present a general numerical platform for designing accurate, efficient, and stable numerical algorithms for incompressible hydrodynamic models that obeys the thermodynamical laws. The obtained numerical schemes are…

Numerical Analysis · Mathematics 2021-03-04 Jia Zhao

We introduce a new Rigid-Field Hydrodynamics approach to modeling the magnetospheres of massive stars in the limit of very-strong magnetic fields. Treating the field lines as effectively rigid, we develop hydrodynamical equations describing…

Astrophysics · Physics 2009-11-13 R. H. D. Townsend , S. P. Owocki , A. ud-Doula