Bulk viscous fluid Bianachi type-V string cosmological model in general relativity

2017 ◽  
Author(s):  
Reena Behal ◽  
D. P. Shukla
Keyword(s):  
General Relativity ◽  
Cosmological Model ◽  
Viscous Fluid ◽  
String Cosmological Model ◽  
Bulk Viscous Fluid ◽  
Bulk Viscous ◽  
Type V

Bianchi Type-V Bulk Viscous Fluid String Dust Cosmological Model In General Relativity

2005 ◽  
Vol 300 (4) ◽  
pp. 387-394 ◽  
Author(s):  
Raj Bali ◽  
Deo Karan Singh
Keyword(s):  
General Relativity ◽  
Cosmological Model ◽  
Viscous Fluid ◽  
Bianchi Type ◽  
Bulk Viscous Fluid ◽  
Bulk Viscous ◽  
Type V ◽  
Bianchi Type V

Bianchi type-I bulk viscous fluid string dust magnetized cosmological model in general relativity

Pramana ◽  
2004 ◽  
Vol 63 (3) ◽  
pp. 481-490 ◽  
Author(s):  
Raj Bali ◽  
Anjali
Keyword(s):  
General Relativity ◽  
Cosmological Model ◽  
Viscous Fluid ◽  
Bianchi Type ◽  
Type I ◽  
Bianchi Type I ◽  
Bulk Viscous Fluid ◽  
Bulk Viscous

scholarly journals PLANE-SYMMETRIC INHOMOGENEOUS BULK VISCOUS COSMOLOGICAL MODELS WITH VARIABLE Λ

2003 ◽  
Vol 12 (05) ◽  
pp. 941-951 ◽  
Author(s):  
ANIRUDH PRADHAN ◽  
HARE RAM PANDEY
Keyword(s):  
Cosmological Model ◽  
Viscous Fluid ◽  
Cosmological Constant ◽  
Ad Hoc ◽  
Fluid Distribution ◽  
Geometric Features ◽  
Plane Symmetric ◽  
Bulk Viscous Fluid ◽  
Variable Λ ◽  
Bulk Viscous

A plane-symmetric non-static cosmological model representing a bulk viscous fluid distribution has been obtained which is inhomogeneous and anisotropic and a particular case of which is gravitationally radiative. Without assuming any ad hoc law, we obtain a cosmological constant as a decreasing function of time. The physical and geometric features of the models are also discussed.

scholarly journals Bianchi type V Ih Bulk-Viscous String Cosmological Model in f(R) Gravity

2019 ◽  
Vol 1344 ◽  
pp. 012038
Author(s):  
M. Vijaya Santhi ◽  
Y. Sobhanbabu ◽  
B. J. M. Rao
Keyword(s):  
Cosmological Model ◽  
Bianchi Type ◽  
String Cosmological Model ◽  
Bulk Viscous ◽  
Type V ◽  
Bianchi Type V

scholarly journals Kaluza–Klein Bulk Viscous Fluid Cosmological Models and the Validity of the Second Law of Thermodynamics in f(R, T) Gravity

2017 ◽  
Vol 72 (4) ◽  
pp. 365-374 ◽  
Author(s):  
Gauranga Charan Samanta ◽  
Ratbay Myrzakulov ◽  
Parth Shah
Keyword(s):  
Cosmological Model ◽  
Viscous Fluid ◽  
Second Law Of Thermodynamics ◽  
Second Law ◽  
Field Equations ◽  
Geometrical Properties ◽  
Bulk Viscous Fluid ◽  
Bulk Viscous ◽  
Two Stages ◽  
Kaluza Klein

Abstract:The authors considered the bulk viscous fluid in f(R, T) gravity within the framework of Kaluza–Klein space time. The bulk viscous coefficient (ξ) expressed as $\xi = {\xi _0} + {\xi _1}{{\dot a} \over a} + {\xi _2}{{\ddot a} \over {\dot a}},$ where ξ0, ξ1, and ξ2 are positive constants. We take p=(γ−1)ρ, where 0≤γ≤2 as an equation of state for perfect fluid. The exact solutions to the corresponding field equations are given by assuming a particular model of the form of f(R, T)=R+2f(T), where f(T)=λT, λ is constant. We studied the cosmological model in two stages, in first stage: we studied the model with no viscosity, and in second stage: we studied the model involve with viscosity. The cosmological model involve with viscosity is studied by five possible scenarios for bulk viscous fluid coefficient (ξ). The total bulk viscous coefficient seems to be negative, when the bulk viscous coefficient is proportional to ${\xi _2}{{\ddot a} \over {\dot a}},$ hence, the second law of thermodynamics is not valid; however, it is valid with the generalised second law of thermodynamics. The total bulk viscous coefficient seems to be positive, when the bulk viscous coefficient is proportional to $\xi = {\xi _1}{{\dot a} \over a},$$\xi = {\xi _1}{{\dot a} \over a} + {\xi _2}{{\ddot a} \over {\dot a}}$ and $\xi = {\xi _0} + {\xi _1}{{\dot a} \over a} + {\xi _2}{{\ddot a} \over {\dot a}},$ so the second law of thermodynamics and the generalised second law of thermodynamics is satisfied throughout the evolution. We calculate statefinder parameters of the model and observed that it is different from the ∧CDM model. Finally, some physical and geometrical properties of the models are discussed.

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