On the combined use of friction matrices and dissipation potentials in thermodynamic modeling

Abstract

Gradient flows and generalized gradient flows, associated with friction matrices and dissipation potentials, respectively, are usually regarded as two alternative possibilities to choose from in modeling irreversible time evolution in nonequilibrium thermodynamics. We here argue that these two possibilities actually need to be combined and we address a number of physical and mathematical issues associated with this task. Dimensional considerations provide important insights into these issues.