Anisotropic fluids with multifluid components

Abstract

The anisotropic-fluid interpretation of a stress-energy tensor formed from the sum of three tensors, each of which is the energy-momentum tensor of a perfect fluid or a null fluid in the special case that the fluids four-velocities are linearly dependent, is studied. The anisotropic-fluid model formed by an arbitrary number of perfect fluids and null fluids is also studied in the particular case that all the fluids' four-velocities lay on a timelike two-plane. The anisotropic-fluid interpretation of the Bondi model of self-gravitating spheres is presented. The particular case of an anisotropic-fluid model formed with three perfect fluids with a stiff equation of state, and the particular case of two null and one perfect fluid with a p=\ensuremath{\rho} equation of state, are used as sources of the Einstein equations for a cylindrically symmetric spacetime, and these last equations are solved. Also, for these particular cases the generalization for an arbitrary number of fluid components is indicated.