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We investigate the equations of anisotropic incompressible viscous fluids in $\R^3$, rotating around an inhomogeneous vector $B(t, x_1, x_2)$. We prove the global existence of strong solutions in suitable anisotropic Sobolev spaces for…

Analysis of PDEs · Mathematics 2009-11-13 Mohamed Majdoub , Marius Paicu

A new class of cylindrically symmetric inhomogeneous cosmological models for perfect fluid distribution with electromagnetic field is obtained in the context of Lyra's geometry. We have obtained two types of solutions by considering the…

General Relativity and Quantum Cosmology · Physics 2010-04-15 Anirudh Pradhan , Priya Mathur

We introduce a notion of stability for non-autonomous Hamiltonian flows on two-dimensional annular surfaces. This notion of stability is designed to capture the sustained twisting of particle trajectories. The main Theorem is applied to…

Analysis of PDEs · Mathematics 2024-08-30 Theodore D. Drivas , Tarek M. Elgindi , In-Jee Jeong

We construct perfect fluid metrics corresponding to spacelike surfaces invariant under a 1-dimensional group of isometries in 3-dimensional Minkowski space. Under additional assumptions we obtain new cosmological solutions of Bianchi type…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Adam Szereszewski , Jacek Tafel

We consider equations of the type: \[\partial_t \omega = \omega R(\omega),\] for general linear operators $R$ in any spatial dimension. We prove that such equations almost always exhibit finite-time singularities for smooth and localized…

Analysis of PDEs · Mathematics 2024-07-24 Roberta Bianchini , Tarek M. Elgindi

We study the future stability of cosmological fluids, in spacetimes with an accelerated expansion, which exhibit extreme tilt behavior, ie. their fluid velocity becoming asymptotically null at timelike infinity. It has been predicted in the…

Analysis of PDEs · Mathematics 2024-04-11 Grigorios Fournodavlos , Elliot Marshall , Todd A. Oliynyk

Via a straightforward integration of the Einstein equations with cosmological constant, all static circularly symmetric perfect fluid 2+1 solutions are derived. The structural functions of the metric depend on the energy density, which…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Alberto A. Garcia , Cuauhtemoc Campuzano

We study the large-time behavior of finite-energy weak solutions for the Vlasov-Navier-Stokes equations in a two-dimensional torus. We focus first on the homogeneous case where the ambient (incompressible and viscous) fluid carrying the…

Analysis of PDEs · Mathematics 2025-12-02 Raphaël Danchin , Ling-Yun Shou

We investigate $(n+1)$-dimensional string-dilaton cosmology with effective dilaton potential in presence of perfect-fluid matter.We get exact solutions parametrized by the constant $\gam$ of the state equation $p=(\gam-1)\rho$, the spatial…

General Relativity and Quantum Cosmology · Physics 2008-11-26 S. Capozziello , G. Lambiase , R. Capaldo

The exactly solvable quantum model of the homogeneous, isotropic and closed universe in the matter-energy production epoch is considered. It is assumed that the universe is originally filled with a uniform scalar field and a perfect fluid…

General Relativity and Quantum Cosmology · Physics 2011-07-19 V. E. Kuzmichev , V. V. Kuzmichev

For a freely evolving granular fluid, the buildup of spatial correlations in density and flow field is described using fluctuating hydrodynamics. The theory for incompressible flows is extended to the general, compressible case, including…

Statistical Mechanics · Physics 2009-10-30 T. P. C. van Noije , M. H. Ernst , R. Brito

We examine the evolution of a universe comprising two interacting fluids, which interact via a term proportional to the product of their densities. In the case of two matter fluids it is shown that the ratio of the densities tends to a…

General Relativity and Quantum Cosmology · Physics 2011-05-13 Sean Z. W. Lip

Vorticity is ubiquitous in nature however, to date, studies of vorticity in cosmology and the early universe have been quite rare. In this paper, based on a talk in session CM1 of the 13th Marcel Grossmann Meeting, we consider vorticity…

Cosmology and Nongalactic Astrophysics · Physics 2012-10-09 Adam J. Christopherson , Karim A. Malik

Bianchi I cosmological models consisting of a fluid with both bulk and shear viscosity are studied. It is shown how the dynamical importance of the shear and the fluid density change in the course of evolution. Exact solutions with an…

General Relativity and Quantum Cosmology · Physics 2021-03-15 A. Banerjee , S. B. Duttachoudhury , Abhik Kumar Sanyal

The equations describing a two-component cosmological fluid with linearized density perturbations are investigated in the small wavelength or large $k$ limit. The equations are formulated to include a baryonic component, as well as either a…

Astrophysics · Physics 2009-11-11 R. M. Gailis , N. E. Frankel

We give a brief review of some aspects of inhomogeneous viscous fluids in a flat Friedmann-Robertson-Walker Universe. In general, it is pointed out that several fluid models may bring the future Universe evolution to become singular, with…

General Relativity and Quantum Cosmology · Physics 2013-11-19 R. Myrzakulov , L. Sebastiani , S. Zerbini

We use the dynamical systems approach to investigate the Bianchi type VIII models with a tilted $\gamma$-law perfect fluid. We introduce expansion-normalised variables and investigate the late-time asymptotic behaviour of the models and…

General Relativity and Quantum Cosmology · Physics 2010-11-05 Sigbjorn Hervik , Woei Chet Lim

In the present letter, we consider homogeneous and isotropic noncommutative cosmological models induced by a symplectic formalism coupled to phantom perfect fluids and a cosmological constant. After computing the field equations, we solve…

General Relativity and Quantum Cosmology · Physics 2020-01-08 G. Oliveira-Neto , L. G. Rezende Rodrigues

We establish the existence of a stable family of solutions to the Euler equations on Kasner backgrounds near the singularity with the full expected asymptotic data degrees of freedom and no symmetry or isotropy restrictions. Existence is…

Analysis of PDEs · Mathematics 2025-02-17 Florian Beyer , Todd A. Oliynyk

In this paper, the study of the gravitational collapse of cylindrically distributed two perfect fluid system has been carried out. It is assumed that the collapsing speeds of the two fluids are very large. We explore this condition by using…

General Relativity and Quantum Cosmology · Physics 2008-11-26 M. Sharif , Zahid Ahmad
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