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Related papers: A two-stream formalism for the convective Urca pro…

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We study the dynamics associated with the extension of turbulent convective motions from a convection zone (CZ) into a stable region (RZ) that lies below the latter. For that purpose, we have run a series of three-dimensional direct…

Solar and Stellar Astrophysics · Physics 2019-01-16 Lydia Korre , Pascale Garaud , Nicholas Brummell

Tropical precipitation extremes are expected to strengthen with warming, but quantitative estimates remain uncertain because of a poor understanding of changes in convective dynamics. This uncertainty is addressed here by analyzing…

Atmospheric and Oceanic Physics · Physics 2020-04-22 Tristan H. Abbott , Timothy W. Cronin , Tom Beucler

It has been recently suggested that white dwarfs generate magnetic fields in a process analogous to the Earth. The crystallization of the core creates a compositional inversion that drives convection, and combined with rotation, this can…

Solar and Stellar Astrophysics · Physics 2022-05-25 Sivan Ginzburg , Jim Fuller , Adela Kawka , Ilaria Caiazzo

Convective core overshooting has a strong influence on the evolution of stars of moderate and high mass. Studies of double-lined eclipsing binaries and stellar oscillations have renewed interest in the possible dependence of overshooting on…

Solar and Stellar Astrophysics · Physics 2017-11-01 Antonio Claret , Guillermo Torres

We study a singular-limit problem arising in the modelling of chemical reactions. At finite {\epsilon} > 0, the system is described by a Fokker-Planck convection-diffusion equation with a double-well convection potential. This potential is…

Analysis of PDEs · Mathematics 2014-09-16 Steffen Arnrich , Alexander Mielke , Mark A. Peletier , Giuseppe Savaré , Marco Veneroni

How many fraction of gas available at the outer boundary can finally fall onto the black hole is an important question. It determines the observational appearance of accretion flows, and is also related with the evolution of black hole mass…

High Energy Astrophysical Phenomena · Physics 2010-06-14 Feng Yuan , De-Fu Bu

How many fraction of gas available at the outer boundary can finally fall onto the black hole is an important question. It determines the observational appearance of accretion flows, and is also related with the evolution of black hole mass…

High Energy Astrophysical Phenomena · Physics 2015-05-18 Feng Yuan , Defu Bu

In this paper, we develop a formalism in order to incorporate the contribution of internal gravity waves to the transport of angular momentum and chemicals over long time-scales in stars. We show that the development of a double peaked…

Astrophysics · Physics 2009-11-11 S. Talon , C. Charbonnel

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 are concerned with the asymptotic behaviour of classical solutions of systems of the form u_t = Au_xx + f(u, u_x), x in R, t>0, u(x,t) a vector in RN, with u(x,0)= U(x), where A is a positive-definite diagonal matrix and f is a…

Analysis of PDEs · Mathematics 2007-05-23 E. C. M. Crooks

In accreting WDs approaching the Chandrasekhar limit, hydrostatic carbon burning precedes the dynamical breakout. During this \textit{simmering} phase, $e-$captures are energetically favored in the central region of the star, while…

Solar and Stellar Astrophysics · Physics 2022-02-23 Luciano Piersanti , Eduardo Bravo , Oscar Straniero , Sergio Cristallo , Inmaculada Dominguez

A framework of finite-velocity model based Boltzmann equation has been developed for convection-diffusion equations. These velocities are kept flexible and adjusted to control numerical diffusion. A flux difference splitting based kinetic…

Numerical Analysis · Mathematics 2024-10-01 S. V. Raghurama Rao , K. S. Shrinath , Ankit Ruhi , Veeredhi Vasudeva Rao

When the flow is sufficiently rarefied, a temperature gradient, for example, between two walls separated by a few mean free paths, induces a gas flow---an observation attributed to the thermo-stress convection effects at microscale. The…

In this paper, a unified framework for particulate two-phase flow will be presented with a wide range of solid-particle concentration from dilute to dense limit. The two phase flow is simulated by two coupled flow solvers, i.e., the…

Fluid Dynamics · Physics 2022-02-23 Xiaojian Yang , Wei Shyy , Kun Xu

Inertial particles in turbulent flows are characterised by preferential concentration and segregation and, at sufficient mass loading, dense particle clusters may spontaneously arise due to momentum coupling between the phases. These…

Fluid Dynamics · Physics 2019-01-30 Alessio Innocenti , Rodney O Fox , Sergio Chibbaro

We study the bulk viscosity of moderately hot and dense, neutrino-transparent relativistic $npe\mu$ matter arising from weak-interaction direct Urca processes. This work parallels our recent study of the bulk viscosity of $npe\mu$ matter…

Nuclear Theory · Physics 2023-10-17 Mark Alford , Arus Harutyunyan , Armen Sedrakian

Non-local, time-dependent convection models have been used to explain the location of double-mode pulsations in Cepheids in the HR diagram as well as the existence and location of the red edge of the instability strip. These properties are…

Solar and Stellar Astrophysics · Physics 2015-04-14 Eva Mundprecht , Herbert J. Muthsam , Friedrich Kupka

A ubiquitous arrangement in nature is a free-flowing fluid coupled to a porous medium, for example a river or lake lying above a porous bed. Depending on the environmental conditions, thermal convection can occur and may be confined to the…

Fluid Dynamics · Physics 2022-12-21 Matthew McCurdy , Nicholas J. Moore , Xiaoming Wang

Theoretical descriptions of convective overshooting often rely on a one-dimensional parameterization of the flow called the filling factor for convection. Several definitions of the filling factor have been developed, based on: (1) the…

Solar and Stellar Astrophysics · Physics 2024-12-04 M. -G. Dethero , J. Pratt , D. G. Vlaykov , I. Baraffe , T. Guillet , T. Goffrey , A. Le Saux , A. Morison

We discuss slowly-rotating, general relativistic, superfluid neutron stars in the Hartle-Thorne formulation. The composition of the stars is described by a simple two-fluid model which accounts for superfluid neutrons and all other…

General Relativity and Quantum Cosmology · Physics 2023-03-21 Eneko Aranguren , José A. Font , Nicolas Sanchis-Gual , Raül Vera