FIZIKA B 18 (2009) 2, 6180
PLANE SYMMETRIC VISCOUS FLUID UNIVERSE WITH DECAYING VACUUM ENERGY DENSITY
L
ANIRUDH PRADHAN
Department of Mathematics, Hindu Postgraduate College, Zamania232 331,
Ghazipur, India
Email addresses: pradhan@iucaa.ernet.in
, acpradhan@yahoo.com
Received 10 March 2009; Accepted 6 May 2009
Online 13 July 2009
Plane symmetric viscous fluid cosmological models of the universe with a
variable cosmological term are investigated. The viscosity coefficient of bulk
viscous fluid is assumed to be a power function of mass density, whereas the
coefficient of shear viscosity is taken as a constant. To get the deterministic
solutions of the Einstein's field equations, the free gravitational field is
assumed to be of type D which is of the next order in the hierarchy of Petrov
classification. The cosmological constant L is found
to be a decreasing function of time and positive which is corroborated by the
results from recent supernovae Ia observations. The physical and geometric
aspects of the models are discussed.
PACS numbers: 98.80.Es, 98.80.k
UDC 52423, 524.83
Keywords: plane symmetric universe, viscous fluid models, decaying
L
