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We analyze stellar convection with the aid of 3D hydrodynamic simulations, introducing the turbulent cascade into our theoretical analysis. We devise closures of the Reynolds-decomposed mean field equations by simple physical modeling of…

Astrophysics · Physics 2011-02-11 David Arnett , Casey Meakin , P. A. Young

Mixing in the convective core is quite uncertain in core helium burning stars. In order to explore the overshooting mixing beyond the convective core, we incorporated the $k$-$\omega$ proposed by Li (2012, 2017) into MESA, and investigated…

Solar and Stellar Astrophysics · Physics 2018-08-15 Yan Li , Xing-hao Chen , He-ran Xiong , Jun-jun Guo , Xue-fei Chen , Zhan-wen Han

We present detailed evolutionary calculations focused on the evolution of intermediate mass stars with 3 Msun < M < 9 Msun of metallicity typical of the Large Magellanic Cloud (LMC), i.e. Z=0.008. We compare carefully the models calculated…

Astrophysics · Physics 2009-11-11 P. Ventura , M. Castellani , C. W. Straka

Our knowledge of stellar evolution is driven by one-dimensional (1D) simulations. 1D models, however, are severely limited by uncertainties on the exact behaviour of many multi-dimensional phenomena occurring inside stars, affecting their…

Solar and Stellar Astrophysics · Physics 2023-05-26 F. Rizzuti , R. Hirschi , W. D. Arnett , C. Georgy , C. Meakin , A. StJ. Murphy , T. Rauscher , V. Varma

Based on the turbulent convection model (TCM) of Li & Yang (2007), we have studied the characteristics of turbulent convection in the envelopes of 2 and 5M stars at the RGB and AGB phases. The TCM has been applied successfully in the whole…

Solar and Stellar Astrophysics · Physics 2015-05-28 X. -J. Lai , Y. Li

A one-dimensional turbulent convection model in the form of a time-dependent diffusion equation for the turbulent energy is incorporated into our numerical pulsation code. The effect of turbulent convection on the structural rearrangement…

Astrophysics · Physics 2016-08-30 P. A. Yecko , Z. Kollath , J. R. Buchler

Asteroseismology of non-radial pulsations in Hot B Subdwarfs (sdB stars) offers a unique view into the interior of core-helium-burning stars. Ground-based and space-borne high precision light curves allow for the analysis of pressure and…

Solar and Stellar Astrophysics · Physics 2017-11-08 J. -T. Schindler , Elizabeth M. Green , W. David Arnett

White dwarfs with metal-polluted atmospheres have been studied widely in the context of the accretion of rocky debris from evolved planetary systems. One open question is the geometry of accretion and how material arrives and mixes in the…

We consider the competition of the different physical processes that can affect the evolution of a flame bubble in a Type Ia supernovae -- burning, turbulence and buoyancy. Even in the vigorously turbulent conditions of a convecting white…

Astrophysics · Physics 2008-11-26 M. Zingale , L. J. Dursi

The dynamics of flame propagation in systems with infinite Lewis number and spatially discretized sources of heat release is examined, which is applicable to the combustion of suspensions of fuel particles in air. The system is analyzed…

Fluid Dynamics · Physics 2016-06-14 XiaoCheng Mi , Andrew J. Higgins , Samuel Goroshin , Jeffrey M. Bergthorson

Large Eddy Simulations with flamelet-based thermochemistry are used to investigate the behaviour of a premixed hydrogen-air flame stabilised by a bluff-body. Validation against experimental data is carried out first to demonstrate the…

Fluid Dynamics · Physics 2026-03-20 Antonio Masucci , Gioele Ferrante , Tiziano Ghisu , Andrea Giusti , Ivan Langella

We present 1D numerical simulations aimed at studying the hot-flasher scenario for the formation of He-rich subdwarf stars. Sequences were calculated for a wide range of metallicities and physical assumptions, such as the stellar mass at…

Astrophysics · Physics 2008-10-31 M. M. Miller Bertolami , L. G. Althaus , K. Unglaub , A. Weiss

Understanding the dynamics of premixed flames that propagates in confined systems is important in a wide range of applications. The study of premixed flames propagating in a closed channel covers a variety of complexities related to flame…

We compute full evolutionary sequences of red giant branch stars close to the luminosity bump by including state of the art composition transport prescriptions for the thermohaline mixing regimes. In particular we adopt a self-consistent…

Solar and Stellar Astrophysics · Physics 2015-05-27 F. C. Wachlin , M. M. Miller Bertolami , L. G. Althaus

In this work, we investigate the impact of uncertainties due to convective boundary mixing (CBM), commonly called `overshoot', namely the boundary location and the amount of mixing at the convective boundary, on stellar structure and…

Solar and Stellar Astrophysics · Physics 2020-07-20 Etienne A. Kaiser , Raphael Hirschi , W. David Arnett , Cyril Georgy , Laura J. A. Scott , Andrea Cristini

Gibson scaling and related properties of flame-surface geometry in turbulent premixed combustion are demonstrated using a novel computational model, Deterministic Turbulent Mixing (DTM). In DTM, turbulent advection is represented by a…

Astrophysics · Physics 2007-05-23 J. C. Niemeyer , A. R. Kerstein

During most stages of stellar evolution the nuclear burning of lighter to heavier elements results in a radial composition profile which is stabilizing against buoyant acceleration, with light material residing above heavier material.…

Solar and Stellar Astrophysics · Physics 2015-05-30 M. Mocák , Casey A. Meakin , E. Müller , L. Siess

We perform large-scale numerical simulations of convection in 3D porous media at Rayleigh-Darcy numbers up to $Ra=8\times10^4$. To investigate the convective mixing of carbon dioxide (CO$_2$) in geological formations, we consider a…

Fluid Dynamics · Physics 2025-03-27 Marco De Paoli , Francesco Zonta , Lea Enzenberger , Eliza Coliban , Sergio Pirozzoli

The influence of extended convective mixing (overshoot) on asymptotic giant branch stellar evolution is investigated in detail. The extended mixing is treated time-dependently, and the efficiency declines exponentially with the geometric…

Astrophysics · Physics 2007-05-23 Falk Herwig

It is known that unconfined dust explosions typically starts off with a relatively weak primary flame followed by a severe secondary explosion. We show that clustering of dust particles in a temperature stratified turbulent flow ahead of…

Fluid Dynamics · Physics 2017-05-18 M. Liberman , N. Kleeorin , I. Rogachevskii , N. E. L. Haugen