Nonequilibrium temperatures, heat waves, and nonlinear heat transport equations

V. A. Cimmelli, A. Sellitto, D. Jou

Research output: Contribution to journalArticleResearchpeer-review

80 Citations (Scopus)


A dynamical nonequilibrium temperature has been proposed to describe relaxational equations for the heat flux. This temperature provides an alternative description to the Maxwell-Cattaneo equation. In the linear regime and in bulk systems both descriptions are equivalent but this is not so when nonlinear effects are included. Here we explore the influence of nonlinear terms on the phase speed of heat waves in nonequilibrium steady states in both theoretical models and we show that their predictions are different. This could allow to explore which description is more suitable, when experiments on these situations will become available. Furthermore, we have analyzed a nonlinear and nonlocal constitutive equation for the heat flux and we have shown its analogy with the Navier-Stokes equation in the regime of phonon hydrodynamics in nanosystems. This analogy allows one to define a dimensionless number for heat flow, analogous to the Reynolds number, and to predict a critical heat flux where nonlinear effects could become dominant. © 2010 The American Physical Society.
Original languageEnglish
Article number054301
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number5
Publication statusPublished - 3 Feb 2010


Dive into the research topics of 'Nonequilibrium temperatures, heat waves, and nonlinear heat transport equations'. Together they form a unique fingerprint.

Cite this