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In fairly general conditions we give explicit (smooth) solutions for the potential flow. We show that, rigorously speaking, the equations of the fluid mechanics have not rotational solutions. However, within the usual approximations of an…

Fluid Dynamics · Physics 2023-09-21 Marian Apostol

We study the relativistic viscous accretion flows around the Kerr black holes. We present the governing equations that describe the steady state flow motion in full general relativity and solve them in 1.5D to obtain the complete set of…

High Energy Astrophysical Phenomena · Physics 2019-07-17 I. Dihingia , Santabrata Das , Debaprasad Maity , Anuj Nandi

Numerical, two-dimensional, time-dependent hydrodynamical models of geometrically thick accretion discs around black holes are presented. Accretion flows with non-effective radiation cooling (ADAFs) can be both convectively stable or…

Astrophysics · Physics 2009-09-25 Igor V. Igumenshchev

A mathematical model describing the flow of two-phase fluids in a bounded container $\Omega$ is considered under the assumption that the phase transition process is influenced by inertial effects. The model couples a variant of the…

Analysis of PDEs · Mathematics 2019-06-14 Gianluca Favre , Giulio Schimperna

We study spatial analyticity properties of solutions of the Navier-Stokes equations and obtain new growth rate estimates for the analyticity radius. We also study stability properties of strong global solutions of the Navier-Stokes…

Mathematical Physics · Physics 2009-08-10 Ira Herbst , Erik Skibsted

This paper presents two modular grad-div algorithms for calculating solutions to the Navier-Stokes equations (NSE). These algorithms add to an NSE code a minimally intrusive module that implements grad-div stabilization. The algorithms do…

Numerical Analysis · Mathematics 2018-05-09 Joseph Anthony Fiordilino , William Layton , Yao Rong

In this paper we investigate the stress concentration problem that occurs when two convex rigid particles are closely immersed in a fluid flow. The governing equations for the fluid flow are the stationary incompressible Navier-Stokes…

Analysis of PDEs · Mathematics 2024-11-26 Haigang Li , Peihao Zhang

In this work we introduce and analyze a novel Hybrid High-Order method for the steady incompressible Navier-Stokes equations. The proposed method is inf-sup stable on general polyhedral meshes, supports arbitrary approximation orders, and…

Numerical Analysis · Mathematics 2018-02-26 Daniele A. Di Pietro , Stella Krell

This work presents a novel stabilization strategy for the Galerkin formulation of the incompressible Navier-Stokes equations, developed to achieve high accuracy while ensuring convergence and compatibility with high-order elements on…

Numerical Analysis · Mathematics 2025-09-05 Antonio Blanco-Casares , Vishal Kumar , Daniel Mira , Oriol Lehmkuhl

The linear stability of a shocked isothermal accretion flow onto a black hole is investigated in the inviscid limit. The outer shock solution, which was previously found to be stable with respect to axisymmetric perturbations, is, however,…

Astrophysics · Physics 2009-11-10 Wei-Min Gu , Thierry Foglizzo

Two main results will be presented in our paper. First, we will prove the regularity of solutions to axially symmetric Navier-Stokes equations under a $log$ supercritical assumption on the horizontally radial component $u^r$ and vertical…

Analysis of PDEs · Mathematics 2023-03-17 Zijin Li , Xinghong Pan

We introduce a rough perturbation of the Navier-Stokes system and justify its physical relevance from balance of momentum and conservation of circulation in the inviscid limit. We present a framework for a well-posedness analysis of the…

Probability · Mathematics 2019-04-22 Martina Hofmanova , James-Michael Leahy , Torstein Nilssen

Fluid flows are typically studied by solving the Navier--Stokes equation. One of the fundamental assumptions of this equation is Stokes' hypothesis. This hypothesis assumes bulk viscosity, to be identically zero. The Stokes' hypothesis is a…

Fluid Dynamics · Physics 2023-03-16 Bhanuday Sharma , Rakesh Kumar

This paper studies inf-sup stable finite element discretizations of the evolutionary Navier--Stokes equations with a grad-div type stabilization. The analysis covers both the case in which the solution is assumed to be smooth and…

Numerical Analysis · Mathematics 2017-05-29 Javier de Frutos , Bosco García-Archilla , Volker John , Julia Novo

In this earliest study of thick accretion disks with viscosity effects, we construct stationary solutions of a relativistic geometrically thick accretion disk in the Schwarzschild spacetime under the influence of shear viscosity and the…

General Relativity and Quantum Cosmology · Physics 2019-09-24 Sayantani Lahiri , Claus Lämmerzahl

Assessing the stability of higher-dimensional rotating black holes requires a study of linearized gravitational perturbations around such backgrounds. We study perturbations of Myers-Perry black holes with equal angular momenta in an odd…

High Energy Physics - Theory · Physics 2009-05-29 Hari K. Kunduri , James Lucietti , Harvey S. Reall

We consider the Cauchy problem for the incompressible Navier-Stokes equations in $\R^3$, and provide a sufficient condition to ensure the smoothness of the solution. It involves only two entries of the velocity Hessian.

Analysis of PDEs · Mathematics 2018-07-10 Zujin Zhang

Most black holes possess accretion disks. Models of such disks inform observations and constrain the properties of the black holes and their surrounding medium. Here, we study isothermal shocks in a thin black hole accretion flow. Modelling…

High Energy Astrophysical Phenomena · Physics 2023-10-27 Eric W. Hester , Geoffrey M. Vasil , Martin Wechselberger

A new exact solution of the Navier-Stokes equation is derived for the compressible flows which are far from equilibrium in the limit of extremely low shear viscosity and relatively large volume viscosity. The closed description of the…

Fluid Dynamics · Physics 2019-03-05 Sergey G. Chefranov , Artem S. Chefranov

We discuss the solution of accretion disk when the black hole is chosen to be rotating. We study, how the fluid properties get affected for different rotation parameters of the black hole. We know that no cosmic object is static in…

Astrophysics · Physics 2009-11-07 Banibrata Mukhopadhyay