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Barber's second self creation theory with bulk viscous fluid source for an LRS Bianchi type-I metric is considered by using deceleration parameter to be constant where the metric potentials are taken as function of $x$ and $t$. The…

General Relativity and Quantum Cosmology · Physics 2009-11-07 A. Pradhan , H. R. Pandey

This study investigates the dynamics of a spatially homogeneous and anisotropic LRS Bianchi type-I universe with viscous fluid in the framework of $f(Q)$ symmetric teleparallel gravity. We assume a linear form for $f(Q)$ and introduce…

General Relativity and Quantum Cosmology · Physics 2024-04-16 M. Koussour , S. H. Shekh , M. Bennai , N. Myrzakulov

A model of a cloud formed by massive strings is used as a source of LRS Bianchi type II with time decaying vacuum energy density $\Lambda$. To construct string cosmological models we have used the energy-momentum tensor for such string as…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-29 Hassan Amirhashchi

We study the evolution of a flat Friedmann-Robertson-Walker Universe, filled with a bulk viscous cosmological fluid, in the presence of time varying ``constants''. The dimensional analysis of the model suggests a proportionality between the…

General Relativity and Quantum Cosmology · Physics 2008-11-26 José Antonio Belinchón , Indrajit Chakrabarty

The viscous Cardassian cosmology is discussed, assuming that there is a bulk viscosity in the cosmic fluid. The dynamical analysis indicates that there exists a singular curve in the phase diagram of viscous Cardassian model. In the viscous…

General Relativity and Quantum Cosmology · Physics 2014-11-18 Chang-Bo Sun , Jia-Ling Wang , Xin-Zhou Li

In this paper, we have analyzed the significance of bulk viscosity in an axially symmetric Bianchi type-I model to study the accelerated expansion of the universe. We have considered four bulk viscosity parameterizations for the…

General Relativity and Quantum Cosmology · Physics 2022-12-21 Archana Dixit , Anirudh Pradhan , Vinod Kumar Bhardwaj , A. Beesham

In this paper, we investigate Bianchi type-$VI$ cosmological model for the universe filled with dark energy and viscous fluid in the presence of cosmological constant. Also, we show accelerating expansion of the universe by drawing volume…

General Relativity and Quantum Cosmology · Physics 2013-08-29 J. Sadeghi , Ali R. Amani , N. Tahmasbi

We are interested in formulating a viscous model of the universe based on The Bianchi Type IV algebra. We first begin by considering a congruence of fluid lines in spacetime, upon which, analyzing their propagation behaviour, we derive the…

Cosmology and Nongalactic Astrophysics · Physics 2012-06-27 Ikjyot Singh Kohli

In this paper, the dynamical behavior of the anisotropic universe has been investigated in $f(R,T)$ theory of gravity. The functional $f(R,T)$ has been rescaled in the form $f(R,T)=\mu R+\mu T$, where $R$ is the Ricci scalar and $T$ is the…

General Physics · Physics 2018-01-08 B. Mishra , S Tarai , S. K. J. Pacif

The research on relativistic universe models with viscous fluids is reviewed. Viscosity may have been of significance during the early inflationary era, and may also be of importance for the late time evolution of the Universe. Bulk…

General Relativity and Quantum Cosmology · Physics 2014-10-01 Iver Brevik , Øyvind Grøn

We study several cosmological models with Bianchi VI_0&III symmetries under the self-similar approach. We find new solutions for the "classical" perfect fluid model as well as for the vacuum model although they are really restrictive for…

General Relativity and Quantum Cosmology · Physics 2009-08-12 José Antonio Belinchón

In this paper, we have constructed the cosmological model of the universe in a two fluids environment with a newly developed mathematical formalism. In order to construct the model Binachi type V (BV) space time is considered with a time…

General Relativity and Quantum Cosmology · Physics 2019-01-23 B. Mishra , Pratik P Ray , R. Myrzakulov

We have investigated the cosmological implications of the bulk viscous cosmological model with variable G and $\Lambda$. These results are found to be compatible with the present observations. The classical cosmological tests for this model…

Astrophysics · Physics 2009-10-31 Arbab I. Arbab

Some properties of cosmological models with a time variable bulk viscous coefficient in presence of adiabatic mater creation and G, c, Lambda variables are investigated in the framework of flat FRW line element. We trivially find a set of…

General Relativity and Quantum Cosmology · Physics 2015-06-25 J. A. Belinchon

We consider an effective viscous pressure as the result of a backreaction of inhomogeneities within Buchert's formalism. The use of an effective metric with a time-dependent curvature radius allows us to calculate the luminosity distance of…

General Relativity and Quantum Cosmology · Physics 2016-04-13 Rodrigo M. Barbosa , G. Eddy , I. Chirinos , Winfried Zimdahl , Oliver F. Piattella

In this paper, we explore an axially symmetric Bianchi type-I model of the universe with bulk viscous fluid as a source of gravitational field under the framework of Einstein's field equations by assuming barotropic bulk viscous pressure as…

General Relativity and Quantum Cosmology · Physics 2025-04-29 G. K. Goswami , Anirudh Pradhan , Vipin Chandra Dubey

A model with flat FRW symmetries and G and Lambda variable,is considered in such a way that the momentum-energy tensor that describes the model is characterized by a bulk viscosity parameter. In this paper it is showed how to apply the…

General Physics · Physics 2007-05-23 J. A. Belinchon

In this study, we investigate a locally rotationally symmetric (LRS) Bianchi type-I cosmological model in non-linear form of $f(Q)$ gravity with observational constraints. We solved the modified Einstein's field equations with a viscous…

General Relativity and Quantum Cosmology · Physics 2025-09-10 Dinesh Chandra Maurya

An analysis is presented of the Bianchi type I cosmological models with a bulk viscosity when the universe is filled with the stiff fluid $p = \epsilon$ while the viscosity is a power function of the energy density, such as $\eta = \alpha…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Wung-Hong Huang

We consider the dynamics of a viscous cosmological fluid in the generalized Randall-Sundrum model for an anisotropic, Bianchi type I brane. To describe the dissipative effects we use the Israel-Hiscock-Stewart full causal thermodynamic…

General Relativity and Quantum Cosmology · Physics 2008-11-26 T. Harko , M. K. Mak