Hans Wilhelm Alt | Searcharxiv

arXiv2018

Relativistic Entropy Inequality

In this paper we apply the entropy principle to the relativistic version of the differential equations describing a standard fluid flow, that is, the equations for mass, momentum, and a system for the energy matrix. These are the second order equations which have been introduced in [3]. Since the principle also says that the entropy equation is a scalar equation, this implies, as we show, that one has to take a trace in the energy part of the system. Thus one arrives at the relativistic mass-momentum-energy system for the fluid. In the procedure we use the well-known Liu-Müller sum [10] in order to deduce the Gibbs relation and the residual entropy inequality.

math-ph↗

arXiv2016

Relativistic equations for the generalized Chapman-Enskog hierarchy

From the Boltzmann equation Chapman and Cowling have firstly motivated a hierarchy of differential equations. I consider a general version of these differential equations which contain the Navier-Stokes system. In the paper I derive a relativistic version of these partial differential equations. This is interesting because in the derivation a covariant version of a time direction is used. This time direction is needed to derive a reduction of the differential equations.

math.AP↗