On numerical relativistic hydrodynamics and barotropic equations of state

Abstract

The characteristic formulation of the relativistic hydrodynamic equations\n(Donat et al 1998 J. Comput. Phys. 146 58), which has been implemented in many\nrelativistic hydro-codes that make use of Godunov-type methods, has to be\nslightly modified in the case of evolving barotropic flows. For a barotropic\nequation of state, a removable singularity appears in one of the eigenvectors.\nThe singularity can be avoided by means of a simple renormalization which makes\nthe system of eigenvectors well defined and complete. An alternative strategy\nfor the particular case of barotropic flows is discussed.\n