Analog gravity in nonisentropic fluids
arXiv:1802.03267
Abstract
The analog acoustic metric has been originally derived for adiabatic acoustic perturbations propagating in an isentropic irrotational ideal fluid. In the framework of a Lagrangian hydrodynamic description we demonstrate that under certain conditions the usual acoustic metric can be derived for nonisentropic fluids. In a special case when the pressure takes a special form and the nonadiabatic perturbations are neglected the adiabatic acoustic perturbations corresponding to massless phonons propagate in an analog metric of the usual type.
15 pages, major revision to match the version accepted in CQG, a section on planar black holes added, a few clarifications added, references added, typos corrected