On hydrodynamics of astrophysical jets

A model for jet acceleration in the funnels of a geometrically thick, radiation-supported disc is constructed. The dynamics of matter lost from the funnels' surface is studied in a general relativistic background and by means of a fully hydrodynamical treatment, including viscosity. Hydrodynamic equations governing the gas flow are derived either for an optically thick or for an optically thin medium. The general behaviour of the solutions is discussed with particular emphasis to their existence and uniqueness. (author)