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A general iterative method proposed some years ago for the description of relativistic collapse, is presented here in comoving coordinates. For doing that we redefine the basic concepts required for the implementation of the method for…

General Relativity and Quantum Cosmology · Physics 2015-03-17 L. Herrera , W. Barreto

We apply the post-quasi--static approximation, an iterative method for the evolution of self-gravitating spheres of matter, to study the evolution of anisotropic non-adiabatic radiating and dissipative distributions in General Relativity.…

General Relativity and Quantum Cosmology · Physics 2010-05-25 C. Peralta , L. Rosales , B. Rodrí guez-Mueller , W. Barreto

A general, iterative, method for the description of evolving self-gravitating relativistic spheres is presented. Modeling is achieved by the introduction of an ansatz, whose rationale becomes intelligible and finds full justification within…

General Relativity and Quantum Cosmology · Physics 2009-11-07 L. Herrera , W. Barreto , A. Di Prisco , N. O. Santos

We review a recently proposed definition of complexity of the structure of self--gravitating fluids \cite{ch1}, and the criterium to define the simplest mode of their evolution. We analyze the origin of these concepts and their possible…

General Relativity and Quantum Cosmology · Physics 2023-04-13 L. Herrera

The recently proposed definition of complexity for static and spherically symmetric self--gravitating systems [1], is extended to the fully dynamic situation. In this latter case we have to consider not only the complexity factor of the…

General Relativity and Quantum Cosmology · Physics 2018-12-19 L. Herrera , A. Di Prisco , J. Ospino

We study the evolution of an anisotropic shear-free fluid with heat flux and kinematic self-similarity of the second kind. We found a class of solution to the Einstein field equations by assuming that the part of the tangential pressure…

General Relativity and Quantum Cosmology · Physics 2014-05-13 R. Chan , M. F. A. da Silva , C. F. C. Brandt

We investigate the evolution of self-gravitating either dissipative or non--dissipative systems satisfying the condition of minimal complexity, and whose areal radius velocity is proportional to the areal radius (quasi-homologous…

General Relativity and Quantum Cosmology · Physics 2020-08-26 L. Herrera , A. Di Prisco , J. Ospino

We apply the postquasistatic approximation, an iterative method for the evolution of self-gravitating spheres of matter, to study the evolution of dissipative and electrically charged distributions in General Relativity. We evolve…

General Relativity and Quantum Cosmology · Physics 2015-03-17 L. Rosales , W. Barreto , C. Peralta , B. Rodrí guez-Mueller

A non-hydrostatic depth-averaged model for dry granular flows is proposed, taking into account vertical acceleration. A variable friction coefficient based on the $\mu(I)$ rheology is considered. The model is obtained from an asymptotic…

We review various approaches to approximating general relativistic effects in hydrodynamic simulations of stellar core collapse and post-bounce evolution. Different formulations of a modified Newtonian gravitational potential are presented.…

Astrophysics · Physics 2009-11-11 Harald Dimmelmeier , Pablo Cerda-Duran , Andreas Marek , Guillaume Faye

The collapsing dynamics of relativistic fluid are explored in $f(R)$ gravity in a detailed systematic manner for the non-static spherically symmetric spacetime satisfying the equation of the conformal Killing vector. With quasi-homologous…

General Relativity and Quantum Cosmology · Physics 2024-10-03 Kazuharu Bamba , Z. Yousaf , M. Z. Bhatti , R. Nazer , Yuki Hashimoto

The stability analysis of self-similar solutions is an important approach to confirm whether they act as an attractor in general non-self-similar gravitational collapse. Assuming that the collapsing matter is a perfect fluid with the…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Eiji Mitsuda , Akira Tomimatsu

Using a framework based on the $1+3$ formalism we carry out a study on axially and reflection symmetric dissipative fluids, in the quasi--static regime. We first derive a set of invariantly defined "velocities", which allow for an…

General Relativity and Quantum Cosmology · Physics 2016-03-08 L. Herrera , A. Di Prisco , J. Ospino , J. Carot

Gravitational collapse in (n+2) dimensional quasi-spherical space-time is studied for a fluid with non vanishing radial pressure. An exact analytic solution is obtained (ignoring the arbitrary integration function) for the equation of state…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Sanjukta Chakraborty , Subenoy Chakraborty , Ujjal Debnath

We apply the postquasistatic approximation to study the evolution of spherically symmetric fluid distributions undergoing dissipation in the form of radial heat flow. For a model which corresponds to an incompressible fluid departing from…

General Relativity and Quantum Cosmology · Physics 2014-11-21 B. Rodríguez-Mueller , C. Peralta , W. Barreto , L. Rosales

We consider a spherically symmetric homogeneous perfect fluid undergoing a gravitational collapse to singularity in the framework of higher-dimensional Rastall gravity in the cases of vanishing and nonvanishing cosmological constants. The…

General Relativity and Quantum Cosmology · Physics 2025-04-08 Golfin Ekatria , Andy Octavian Latief , Fiki Taufik Akbar , Bobby Eka Gunara

In this paper, the quasi static-approximation on the hydrodynamics of compact objects is proposed in $f(R, T)$ gravity, where $R$ is the scalar curvature and $T$ is the trace of stress-energy tensor, by exploring the axial and reflection…

General Relativity and Quantum Cosmology · Physics 2024-08-26 Z. Yousaf , Kazuharu Bamba , M. Z. Bhatti , U. Farwa

In this paper we consider fully discrete approximations of abstract evolution equations, by means of a quasi non-conforming spatial approximation and finite differences in time (Rothe-Galerkin method). The main result is the convergence of…

Analysis of PDEs · Mathematics 2021-07-20 Luigi C. Berselli , Alex Kaltenbach , Michael Ruzicka

This paper contains the latest installment of the authors' project on developing ensemble based data assimilation methodology for high dimensional fluid dynamics models. The algorithm presented here is a particle filter that combines model…

Numerical Analysis · Mathematics 2020-04-22 Colin Cotter , Dan Crisan , Darryl Holm , Wei Pan , Igor Shevchenko

We investigate the dynamics of self-gravitating, spherically-symmetric distributions of fluid through numerical means. In particular, systems involving neutron star models driven far from equilibrium in the strong-field regime of general…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Scott C. Noble
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