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Related papers: Viscosity in spherically symmetric accretion

200 papers

Flow instability and turbulent transition can be well explained using a new proposed theory--Energy gradient theory [1]. In this theory, the stability of a flow depends on the relative magnitude of energy gradient in streamwise direction…

Fluid Dynamics · Physics 2007-05-23 Hua-Shu Dou

This paper concerns the barotropic compressible Navier-Stokes equations in a two-dimensional half-space subject to Navier-slip boundary conditions with vacuum or non-vacuum far-field density. The global existence and large-time behavior of…

Analysis of PDEs · Mathematics 2026-05-29 Qinghao Lei , Weirong Liang

In this work, we ask and answer the question: when is the viscosity of a fluid uniquely determined from spatially sparse measurements of its velocity field? We pose the question mathematically as an optimization problem using the…

Analysis of PDEs · Mathematics 2023-02-23 Animikh Biswas , Joshua Hudson

Analytical treatment of black hole accretion generally presumes the stability of the stationary configuration. Various authors in the past several decades demonstrated the validity of such an assumption for inviscid hydrodynamic flow.…

High Energy Astrophysical Phenomena · Physics 2014-06-17 Sankhasubhra Nag , Deepika B Ananda , Ishita Maity , Tapas K. Das

This paper concerns with the large-time behaviors of the viscous shock profile and rarefaction wave under initial perturbations which tend to space-periodic functions at infinities for the one-dimensional compressible Navier-Stokes-Poisson…

Analysis of PDEs · Mathematics 2023-08-31 Yeping Li , Yu Mei , Yuan Yuan

Consider the dynamics of a layer of viscous incompressible fluid under the influence of gravity. The upper boundary is a free boundary with the effect of surface tension taken into account, and the lower boundary is a fixed boundary on…

Analysis of PDEs · Mathematics 2019-11-12 Yanjin Wang , Zhouping Xin

A new formulation of the Navier-Stokes equation, in terms of the gradient of the total mechanical energy, is derived for the time-averaged flows, and the singular point possibly existing in the Navier-Stokes equation is exactly found.…

Fluid Dynamics · Physics 2014-12-30 Hua-Shu Dou

For two dimensional inhomogeneous Navier-Stokes of incompressible flows, with the assumption that the viscosity depends on the density but with a positive lower bound, using a partial regularity approach, in particular some enhanced decay…

Analysis of PDEs · Mathematics 2016-10-11 Ning Jiang , Yilong Luo

Singularity of Navier-Stokes equations is uncovered for the first time which explains the mechanism of transition of a smooth laminar flow to turbulence. It is found that when an inflection point is formed on the velocity profile in…

Fluid Dynamics · Physics 2020-08-20 Hua-Shu Dou

In this paper, a viscous shock wave under space-periodic perturbation of 1-D isentropic Navier-Stokes system in the half space is investigated. It is shown that if the initial periodic perturbation around the viscous shock wave is small,…

Analysis of PDEs · Mathematics 2024-01-02 Lin Chang , Lin He , Jin Ma

For gas flows, the Navier-Stokes (NS) equations are established by mathematically expressing conservations of mass, momentum and energy. The advantage of the NS equations over the Euler equations is that the NS equations have taken into…

Fluid Dynamics · Physics 2022-12-27 Jinglei Xu , Dong Ma , Pengxin Liu , Lin Bi , Xianxu Yuan , Longfei Chen

Spherically symmetric transonic accretion of a fractal medium has been studied in both the stationary and the dynamic regimes. The stationary transonic solution is greatly sensitive to infinitesimal deviations in the outer boundary…

Astrophysics · Physics 2007-08-30 Nirupam Roy , Arnab K. Ray

We consider the two-dimensional incompressible inhomogeneous Navier-Stokes equations with odd viscosity, where the shear and the odd viscosity coefficients depend continuously on the unknown density function. We establish the existence of…

Analysis of PDEs · Mathematics 2025-08-26 Rebekka Zimmermann

This paper is concerned with the global solvability for the Navier-Stokes equations describing viscous free surface flows of infinite depth in three and higher dimensions. We first prove time weighted estimates of solutions to a linearized…

Analysis of PDEs · Mathematics 2023-11-21 Hirokazu Saito , Yoshihiro Shibata

The stability of a two-dimensional viscous flow between two rotating porous cylinders is studied. The basic steady flow is the most general rotationally-invariant solution of the Navier-Stokes equations in which the velocity has both radial…

Fluid Dynamics · Physics 2015-06-18 Konstantin Ilin , Andrey Morgulis

Consider the time-periodic viscous incompressible fluid flow past a body with non-zero velocity at infinity. This article gives sufficient conditions such that weak solutions to this problem are smooth. Since time-periodic solutions do not…

Analysis of PDEs · Mathematics 2022-12-02 Thomas Eiter

The Stokes equation describes the motion of fluids when inertial forces are negligible compared to viscous forces. In this article, we explore the consequence of parity-violating and non-dissipative (i.e. odd) viscosities on Stokes flows in…

Fluid Dynamics · Physics 2022-02-01 Tali Khain , Colin Scheibner , Michel Fruchart , Vincenzo Vitelli

In the present work, we investigate a numerical one-dimensional solver to the Navier-Stokes equation that retains all terms, including both pressure and dissipation. Solutions to simple examples that illustrate the actions of the nonlinear…

Fluid Dynamics · Physics 2023-03-30 Preben Buchhave , Clara Marika Velte

We study viscous transonic accretion flows in vertical equilibrium in Kerr geometry. We employ the pseudo-Kerr formalism which accurately describes transonic flows around Kerr black holes and is applicable for modelling observational data.…

High Energy Astrophysical Phenomena · Physics 2024-10-01 Abhrajit Bhattacharjee , Sandip K. Chakrabarti

We investigated the instability of advective accretion flow as a consequence of angular momentum transfer in one-dimensional, quasi-spherical transonic accretion flow around a non-rotating black hole. The code is designed to include the…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-09 Seong-Jae Lee , Dongsu Ryu , Indranil Chattopadhyay