Thermodynamics of Continua

This chapter outlines background ideas of thermodynamics, and addresses the thermodynamics of continua. The first law of the thermodynamics, formalized through the heat-friction experiments of Joule in 1843, claims that a thermodynamical system can store and supply energy but its total energy is conserved. Reversible processes are ideal concepts but, in realistic situations, a part of the energy is lost or dissipated due to internal frictions producing heat. The second law of thermodynamics claims that, for the reversible and irreversible processes, the total production of entropy is positive. The chapter shows that the thermodynamical behavior of a continuum is modeled by the momentum tensor. To define completely the dissipative processes of the material, one needs an additional relation called the constitutive law. Before discussing some aspects of the constitutive laws, the chapter characterizes the non-dissipative processes. Finally, it discusses physical interpretation of the Galilean transformations.