Viscous Extended Cosmic Chaplygin Gas with Varying Cosmological Constant in FRW Universe

In this paper, we study the viscous extended cosmic Chaplygin gas whose equation of state reduces to extended Chaplygin gas in the limit omega -> 0 with varying cosmological constant in flat FRW universe. In this framework, we assume the bulk viscosity zeta and cosmological constant Lambda as a linear combination of two terms, one is constant and other is a function of dark energy density rho. We obtain generalized Friedmann equations due to bulk viscosity, cosmological constant and extended cosmic Chaplygin gas. We calculate the time-dependent dark energy density rho for various values of n and alpha = 1/2 both analytically and numerically. We analyse the behaviour of scale factor, Hubble expansion parameter and deceleration parameter graphically and discuss the stability of the model by using square of speed of sound.