English
Related papers

Related papers: Modelling low Mach number stellar hydrodynamics wi…

200 papers

Recent photometric observations of massive stars have identified a low-frequency power excess which appears as stochastic low-frequency variability in light curve observations. We present the oscillation properties of high resolution…

Solar and Stellar Astrophysics · Physics 2024-05-01 William Thompson , Falk Herwig , Paul R. Woodward , Huaqing Mao , Pavel Denissenkov , Dominic M. Bowman , Simon Blouin

Accurate simulations of flows in stellar interiors are crucial to improving our understanding of stellar structure and evolution. Because the typically slow flows are merely tiny perturbations on top of a close balance between gravity and…

Solar and Stellar Astrophysics · Physics 2021-08-18 P. V. F. Edelmann , L. Horst , J. P. Berberich , R. Andrassy , J. Higl , G. Leidi , C. Klingenberg , F. K. Roepke

Our understanding of stellar structure and evolution coming from one-dimensional (1D) stellar models is limited by uncertainties related to multi-dimensional processes taking place in stellar interiors. 1D models, however, can now be tested…

Solar and Stellar Astrophysics · Physics 2022-08-17 F. Rizzuti , R. Hirschi , C. Georgy , W. D. Arnett , C. Meakin , A. StJ. Murphy

Radiation-hydrodynamical simulations of surface convection in low-mass stars can be exploited to derive estimates of i) the efficiency of the convective energy transport in the stellar surface layers; ii) the convection-related photometric…

Astrophysics · Physics 2009-11-13 Hans-G. Ludwig , Elisabetta Caffau , Arunas Kucinskas

We present PHLEGETHON, a fully compressible, Eulerian magnetohydrodynamic (MHD) code designed for multidimensional simulations in stellar astrophysics. The code uses a time-explicit, second-order, finite-volume method optimized to model a…

In this paper we describe our convective hydrocodes for radial stellar pulsation. We adopt the Kuhfuss (1986) model of convection, reformulated for the use in stellar pulsation hydrocodes. Physical as well as numerical assumptions of the…

Astrophysics · Physics 2008-10-13 R. Smolec , P. Moskalik

The hydrodynamic processes operating within stellar interiors are far richer than represented by the best stellar evolution model available. Although it is now widely understood, through astrophysical simulation and relevant terrestrial…

Astrophysics · Physics 2009-11-13 Casey A. Meakin

We formulate low Mach number fluctuating hydrodynamic equations appropriate for modeling diffusive mixing in isothermal mixtures of fluids with different density and transport coefficients. These equations eliminate the fluctuations in…

Numerical Analysis · Mathematics 2016-01-20 A. Donev , A. J. Nonaka , Y. Sun , T. G. Fai , A. L. Garcia , J. B. Bell

We present an analysis of the response of a radiative region to waves generated by a convective region of the star; this wave treatment of the classical problem of ``overshooting'' gives extra mixing relative to the treatment traditionally…

Astrophysics · Physics 2009-11-07 Patrick A. Young , Karen A. Knierman , Jane R. Rigby , David Arnett

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

Broadening and asymmetry of spectral lines in slowly rotating late A-type stars provide evidence for high-amplitude convective motions. The properties of turbulence observed in the A-star atmospheres are not understood theoretically and…

Astrophysics · Physics 2015-06-24 O. Kochukhov , B. Freytag , N. Piskunov , M. Steffen

In this contribution we present initial results of a study on convective boundary mixing (CBM) in massive stellar models using the GENEVA stellar evolution code. Before undertaking costly 3D hydrodynamic simulations, it is important to…

Solar and Stellar Astrophysics · Physics 2015-06-23 Andrea Cristini , Raphael Hirschi , Cyril Georgy , Casey Meakin , David Arnett , Maxime Viallet

Current state-of-the-art computational modeling makes it possible to build realistic models of stellar convection zones and atmospheres that take into account chemical composition, radiative effects, ionization, and turbulence. The standard…

Solar and Stellar Astrophysics · Physics 2021-07-28 Irina N. Kitiashvili , Alan A. Wray

The extent of mixed regions around convective zones is one of the biggest uncertainties in stellar evolution. 1D overshooting descriptions introduce a free parameter ($f_{ov}$) that is in general not well constrained from observations.…

Solar and Stellar Astrophysics · Physics 2021-03-08 Johann Higl , Ewald Mueller , Achim Weiss

Numerical radiation-hydrodynamics (RHD) for non-relativistic flows is a challenging problem because it encompasses processes acting over a very broad range of timescales, and where the relative importance of these processes often varies by…

Instrumentation and Methods for Astrophysics · Physics 2024-07-29 Chong-Chong He , Benjamin D. Wibking , Mark R. Krumholz

We present 3-D hydrodynamical simulations of core convection with a stably stratified envelope of a \unit{25}{\Msun} star in the early phase of the main-sequence. We use the explicit gas-dynamics code \code{PPMstar} which tracks two fluids…

Solar and Stellar Astrophysics · Physics 2024-08-13 Huaqing Mao , Paul Woodward , Falk Herwig , Pavel A. Denissenkov , Simon Blouin , William Thompson , Benjamin McDermott

Based on the Roe solver a new technique that allows to correctly represent low Mach number flows with a discretization of the compressible Euler equations was proposed in Miczek et al.: New numerical solver for flows at various mach…

A low-Mach-number flow, in the laminar regime, has intrinsically two characteristic spatial scales for a given time scale, or two characteristic temporal scales for a given spatial scale, and these dual scales are very different due to the…

Context: Convectively-driven flows play a crucial role in the dynamo processes that are responsible for producing magnetic activity in stars and planets. It is still not fully understood why many astrophysical magnetic fields have a…

Solar and Stellar Astrophysics · Physics 2018-05-09 P. J. Bushby , P. J. Käpylä , Y. Masada , A. Brandenburg , B. Favier , C. Guervilly , M. J. Käpylä

We present multidimensional modeling of convection and oscillations in main-sequence stars somewhat more massive than the Sun, using three separate approaches: 1) Using the 3-D planar StellarBox radiation hydrodynamics code to model the…

Solar and Stellar Astrophysics · Physics 2016-05-17 Joyce A. Guzik , T. H. Morgan , N. J. Nelson , C. Lovekin , K. Kosak , I. N. Kitiashvili , N. N. Mansour , A. Kosovichev