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Related papers: Self-Similar Accretion Flows with Convection

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The paper is concerned with an adjoint complement to the Volume-of-Fluid (VoF) method for immiscible two-phase flows, e.g. air and water, which is widely used in marine engineering due to its computational efficiency. The particular…

Fluid Dynamics · Physics 2021-06-02 Niklas Kühl , Jörn Kröger , Martin Siebenborn , Michael Hinze , Thomas Rung

We study the contribution of advection by thermal velocity fluctuations to the effective diffusion coefficient in a mixture of two identical fluids. The steady-state diffusive flux in a finite system subject to a concentration gradient is…

Mesoscale and Nanoscale Physics · Physics 2015-05-27 A. Donev , A. de la Fuente , J. B. Bell , A. L. Garcia

(Abridged) We study the dynamical evolution of a stationary, axisymmetric, and perfectly conducting cold accretion disk containing a large-scale magnetic field around a Kerr black hole, trying to understand the relation between accretion…

Astrophysics · Physics 2009-11-07 Li-Xin Li

The stratification of entropy and the stratification of angular momentum are closely analogous. Of particular interest is the behavior of disks in which angular momentum transport is controlled by convection, and heat transport by dynamical…

Astrophysics · Physics 2009-10-31 Steven A. Balbus

We present analytical and numerical solutions which describe a hot, viscous, two-temperature accretion flow onto a neutron star or any other compact star with a surface. We assume Coulomb coupling between the protons and electrons, and…

Astrophysics · Physics 2009-11-06 Mikhail V. Medvedev

The eruptive cycles of dwarf novae (DN) are thought to be due to a thermal-viscous instability in the accretion disk surrounding the white dwarf (WD). This model has long been known to imply a stress to pressure ratio \alpha ~0.1 in…

Solar and Stellar Astrophysics · Physics 2018-01-17 N. Scepi , G. Lesur , G. Dubus , M. Flock

We investigate the transport of a solute past isolated sinks in a bounded domain when advection is dominant over diffusion, evaluating the effectiveness of homogenization approximations when sinks are distributed uniformly randomly in…

Fluid Dynamics · Physics 2022-06-28 George F. Price , Igor L. Chernyavsky , Oliver E. Jensen

Radial transport of particles, elements and fluid driven by internal stresses in three-dimensional (3D) astrophysical accretion disks is an important phenomenon, potentially relevant for the outward dust transport in protoplanetary disks,…

High Energy Astrophysical Phenomena · Physics 2017-03-15 Alexander A. Philippov , Roman R. Rafikov

We perform time-dependent, 2DHD numerical simulations to study the dynamics of a slowly rotating accretion flow from sub-pc to pc scales under the irradiation from the central AGN. Compared to previous work, we improve the calculation of…

High Energy Astrophysical Phenomena · Physics 2015-06-15 Chao Liu , Feng Yuan , Jeremiah P. Ostriker , Zhaoming Gan , Xiaohong Yang

In this note we study the accretion disc that arises in hypercritical accretion of $\dot M\sim 10^8 M_{\rm Edd}$ onto a neutron star while it is in common envelope evolution with a massive companion. In order to raise the temperature high…

Astrophysics · Physics 2009-10-31 G. E. Brown , C. -H. Lee , H. A. Bethe

We perform an exhaustive study of the simplest, nontrivial problem in advection-diffusion -- a finite absorber of arbitrary cross section in a steady two-dimensional potential flow of concentrated fluid. This classical problem has been…

Soft Condensed Matter · Physics 2009-11-10 Jaehyuk Choi , Dionisios Margetis , Todd M. Squires , Martin Z. Bazant

The aim of this paper is to study and classify the multiplicity of distinguished limits and asymptotic solutions for the advection equation with a general oscillating velocity field with the systematic use of the two-timing method. Our…

Fluid Dynamics · Physics 2016-05-10 V. A. Vladimirov

In turbulent flows subject to strong background rotation, the advective mechanisms of turbulence are superseded by the propagation of inertial waves, as the effects of rotation become dominant. While this mechanism has been identified…

Fluid Dynamics · Physics 2020-02-19 J. A. Brons , P. J. Thomas , A. Potherat

We consider the problem of optimizing heat transport through an incompressible fluid layer. Modeling passive scalar transport by advection-diffusion, we maximize the mean rate of total transport by a divergence-free velocity field. Subject…

Analysis of PDEs · Mathematics 2019-09-18 Charles R. Doering , Ian Tobasco

Convex relaxations of AC optimal power flow (AC-OPF) problems have attracted significant interest as in several instances they provably yield the global optimum to the original non-convex problem. If, however, the relaxation is inexact, the…

Optimization and Control · Mathematics 2020-03-03 Andreas Venzke , Spyros Chatzivasileiadis , Daniel K. Molzahn

We investigate the impact of gas accretion in streams on the evolution of disc galaxies, using magneto-hydrodynamic simulations including advection and anisotropic diffusion of cosmic rays generated by supernovae as the only source of…

Astrophysics of Galaxies · Physics 2021-10-13 Nicolas Peschken , Michał Hanasz , Thorsten Naab , Dominik Wóltański , Artur Gawryszczak

We present analytical scaling laws for self-similar advection dominated flows. The spectra from these systems range from 10$^{8}$ - 10$^{20}$ Hz, and are determined by considering cooling of electrons through synchrotron, bremsstrahlung,…

Astrophysics · Physics 2009-10-28 Rohan Mahadevan

(abridged) Aims: To study turbulent transport coefficients that describe the evolution of large-scale magnetic fields in turbulent convection. Methods: We use the test field method together with 3D numerical simulations of turbulent…

Astrophysics · Physics 2009-07-29 P. J. Käpylä , M. J. Korpi , A. Brandenburg

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
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