Wave propagation in N-species relativistic flows

Department of Mathematics, University of Messina - Viale Ferdinando Stagno d'Alcontres, 31, 98166 Messina, Italy, EU

^a sgiambo@unime.it
^b vlarosa@unime.it

Received: 10 October 2011
Accepted: 10 April 2012

Abstract

We consider a system of hyperbolic balance laws governing relativistic fluid flow of an arbitrary number of species, in which entropy is produced only by disequilibrium between temperatures of the fluids. We compare two models: one in which thermal equilibrium is attained through a relaxation procedure, and a fully relaxed model. We describe how the relaxation procedure may be made consistent with the second law of thermodynamics. The wave velocities for both models are obtained and compared: the mixture hydrodynamical velocity of the relaxed system is always less than the hydrodynamical velocity of the relaxation system.