Acoustic wave propagation at nonadiabatic conditions: The continuum limit of a thin acoustic layer

Abstract

Existing studies on sound propagation in rarefied gases are extended to consider wave transmission at nonadiabatic ambient conditions, where arbitrarily large reference temperature and density gradients prevail. Asymptotic analysis of the acoustic field is carried out in the limit of small Knudsen numbers and high actuation frequencies, for both mechanical and thermal wall excitations.