Browsing by Author "Pandey, Purnima"

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    Plane symmetric inhomogeneous cosmological models with a perfect fluid in general relativity
    (2006-01-01) Pradhan, Anirudh; Pandey, Purnima; Singh, Sunil Kumar
    In this paper we investigate a class of solutions of Einstein equations for the plane- symmetric perfect fluid case with shear and vanishing acceleration. If these solutions have shear, they must necessarily be non-static. We examine the integrable cases of the field equations systematically. Among the cases with shear we find three classes of solutions.
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    Some Bianchi Type I Viscous fluid cosmological models with a variable cosmological constant
    (2011-07-06) Pradhan, Anirudh; Pandey, Purnima
    Some Bianchi type I viscous fluid cosmological models with a variable cosmological constant are investigated in which the expansion is considered only in two direction i.e. one of the Hubble parameter (H1 = A4 A ) is zero. The viscosity coefficient of bulk viscous fluid is assumed to be a power function of mass density whereas the coefficient of shear viscosity is considered as constant in first case whereas in other case it is taken as proportional to scale of expansion in the model. The cosmological constant Λ is found to be positive and is a decreasing function of time which is supported by results from recent supernovae Ia observations. Some physical and geometric properties of the models are also discussed.