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Related papers: Distributed Burning in Type Ia Supernovae: A Stati…

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A variety of descriptions of the conversion of a neutron into a strange star have appeared in the literature over the years. Generally speaking, these works treat the process as a mere phase transition or ignore everything but microscopic…

High Energy Astrophysical Phenomena · Physics 2010-05-25 J. E. Horvath

Various flame tracking techniques are often used in hydrodynamic simulations. Their use is indispensable when resolving actual scale of the flame is impossible. We show that parameters defining "artificial flame" propagation found from…

Astrophysics · Physics 2007-05-23 Andrey V. Zhiglo

Although the evolution of premixed flames in turbulence has been frequently studied, it is not well understood how small flames interact with large-scale turbulent flow motion. Since this question is of practical importance for the…

Fluid Dynamics · Physics 2020-02-04 Tobias Falkenstein , Seongwon Kang , Heinz Pitsch

Observations of galactic white dwarfs with Gaia have allowed for unprecedented modeling of white dwarf cooling, resolving core crystallization and sedimentary heating from neutron rich nuclei. These cooling sequences are sensitive to the…

Solar and Stellar Astrophysics · Physics 2021-07-07 M. E. Caplan , I. F. Freeman

The effect of turbulence on the heterogeneous (solid-fluid) reactions of solid particles is studied numerically with Direct Numerical Simulations (DNS). A simplified reaction system is used, where the solid-fluid reaction is represented by…

Fluid Dynamics · Physics 2016-07-14 Jonas Krüger , Nils E. L. Haugen , Dhrubaditya Mitra , Terese Løvås

Through the use of axisymmetric 2D hydrodynamic simulations, we further investigate laterally propagating flames in X-ray bursts (XRBs). Our aim is to understand the sensitivity of a propagating helium flame to different nuclear physics.…

High Energy Astrophysical Phenomena · Physics 2023-06-29 Zhi Chen , Michael Zingale , Kiran Eiden

This work presents numerical results on the transport of heat and chemical species by shear-induced turbulence in strongly stratified but thermally diffusive environments. The shear instabilities driven in this regime are sometimes called…

Solar and Stellar Astrophysics · Physics 2016-04-20 Pascale Garaud , Logithan Kulenthirarajah

The problem of premixed flame propagation in wide horizontal tubes is revisited. Employing the on-shell description of flames with arbitrary gas expansion, a nonlinear second-order differential equation for the front position of steady…

Fluid Dynamics · Physics 2015-05-30 Kirill A. Kazakov

We discuss a new phenomenon of turbulent thermal diffusion associated with turbulent transport of aerosols in the atmosphere and in laboratory experiments. The essence of this phenomenon is the appearance of a nondiffusive mean flux of…

Astrophysics · Physics 2020-01-29 A. Eidelman , T. Elperin , N. Kleeorin , A. Krein , I. Rogachevskii , J. Buchholz , G. Gruenefeld

We study the nucleation and growth of flame fronts in slow combustion. This is modeled by a set of reaction-diffusion equations for the temperature field, coupled to a background of reactants and augmented by a term describing random…

Statistical Mechanics · Physics 2015-06-25 Mikko Karttunen , Nikolas Provatas , Tapio Ala-Nissila , Martin Grant

Lean turbulent premixed hydrogen/air flames have substantially increased flame speeds, commonly attributed to differential diffusion effects. In this work, the effect of turbulence on lean hydrogen combustion is studied through Direct…

Fluid Dynamics · Physics 2024-08-20 Matthew X. Yao , Guillaume Blanquart

The critical dimension necessary for a flame to propagate in suspensions of fuel particles in oxidizer is studied analytically and numerically. Two types of models are considered: First, a continuum model, wherein the individual particulate…

Fluid Dynamics · Physics 2019-12-23 Fredric Y. K. Lam , XiaoCheng Mi , Andrew J. Higgins

This paper presents a numerical investigation into the phenomenon of flame spread over thin circular ducts in normal gravity and microgravity environments. Flame spread over such geometry is of significant interest due to its relevance in…

Fluid Dynamics · Physics 2024-04-02 Vipin Kumar , Kambam Naresh , Amit Kumar

A simulation of the thermonuclear explosion of a Chandrasekhar-mass C+O white dwarf, the most popular scenario of a type Ia supernova (SN Ia), is presented. The underlying modeling is pursued in a self-consistent way, treating the…

Astrophysics · Physics 2009-11-13 F. K. Roepke , W. Hillebrandt , W. Schmidt , J. C. Niemeyer , S. I. Blinnikov , P. A. Mazzali

Type Ia supernovae are bright stellar explosions distinguished by standardizable light curves that allow for their use as distance indicators for cosmological studies. Despite their highly successful use in this capacity, the progenitors of…

Solar and Stellar Astrophysics · Physics 2015-06-05 Alan C. Calder , Brendan K. Krueger , Aaron P. Jackson , Dean M. Townsley , Edward F. Brown , Francis X. Timmes

Rayleigh-B\'enard convection in the turbulent regime is studied using statistical methods. Exact evolution equations for the probability density function of temperature and velocity are derived from first principles within the framework of…

Fluid Dynamics · Physics 2011-03-04 J. Lülff , M. Wilczek , R. Friedrich

We present the first vertically resolved hydrodynamic simulations of a laterally propagating, deflagrating flame in the thin helium ocean of a rotating accreting neutron star. We use a new hydrodynamics solver tailored to deal with the…

High Energy Astrophysical Phenomena · Physics 2015-06-12 Yuri Cavecchi , Anna L. Watts , Jonathan Braithwaite , Yuri Levin

We present first results of three-dimensional (3D-) calculations of turbulent and degenerate hydrogen-burning on top of a C+O white dwarf of one solar mass. The simulations are carried out by means of a code which solves Euler's equation…

Astrophysics · Physics 2007-05-23 A. Kercek , W. Hillebrandt , J. W. Truran

We investigate experimentally phenomenon of turbulent thermal diffusion of micron-size solid particles in an inhomogeneous convective turbulence forced by one vertically-oriented oscillating grid in an air flow. This effect causes formation…

Fluid Dynamics · Physics 2024-04-19 E. Elmakies , O. Shildkrot , N. Kleeorin , A. Levy , I. Rogachevskii

Type Ia supernovae (SNe Ia) play a critical role in astrophysics, yet their origin remains mysterious. A crucial physical mechanism in any SN Ia model is the initiation of the detonation front which ultimately unbinds the white dwarf…

Solar and Stellar Astrophysics · Physics 2019-05-15 Robert T. Fisher , Pritom Mozumdar , Gabriel O. Casabona