Statistical Energy Analysis and the second principle of thermodynamics

Statistical Energy Analysis is a statistical method in vibroacoustics entirely based on the application of energy balance that is the first principle of thermodynamics. In this study, the definition of vibrational entropy is introduced for sub-systems containing energy and modes. The rate of entropy production at interfaces between sub-systems is also derived. Finally, in steady-state condition, an entropy equilibrium is reached. The meaning of entropy and some implications of this entropy balance are also discussed.