A simple approach for evaluation of cut-on condition of higher order modes in inhomogeneous uniform acoustic waveguides.

Abstract Uniform acoustic waveguides in initially quiescent inhomogeneous media are governed by Bergmann's wave equation. The transverse modes are independent of the ambient gradient, but there is a void of papers on the cut-on conditions of the higher order axial modes. This paper presents a sufficient cut-on condition and discusses its application to hard-walled ducts in which the mean temperature varies linearly and exponentially along the duct axis. [ABSTRACT FROM AUTHOR]