Anisotropic Cosmological Model with a Generalized Chaplygin Gas

*The shear tensor measures any tendency of an initially spherical ball ofmatter to become distorted into an ellipsoid shape. The vorticity tensormeasures any tendency of nearby world lines to twist about one another*The right hand side of Raychaudhuri’s equation consists of two types ofterms:1-terms which promote collapse:-expansion scalar-shearingPositive trace of the tidal tensor2-terms which oppose collapse:-vorticity (corresponding to Newtonian centrifugal forces)Positive divergence of the acceleration vector