Boundary conditions for the relativistic motion of two immiscible fluids

The relativistic motion of two immiscible fluids, separated by an hypersurface μ, is considered in a general space-time. In the frame of the discontinuous models of the interface phase, a quite general form of the relativistic balance equations at the interface is derived, in the presence of both interface densities and currents. The set of the interface costitutive relations connecting thermodynamic fluxes and generalized forces is also derived on the basis of the postulates of linear irreversible thermodynamics. The resulting complete set of boundary conditions at the interface is discussed. (author)