Growth and Propagation of Acoustic Waves of Nonuniform Sound Speed Within a Plane-Walled Enclosure

Abstract

Abstract The propagation of acoustic waves through nonuniform temperature fields may suffer distortion due to local sound speed variations. This paper considers the case of the generation and propagation of acoustic waves through a nonuniform temperature field where the spatial variations are caused by eddy current heating of a fluid layer. Numerical solutions to the variable coefficient inhomogeneous wave equation are presented for the case where the fluid is excited in the transverse direction and the adjoining walls are acoustically hard. Progressive and dispersive waves can be clearly distinguished in the numerical results with a dispersive wave speed value within 1.5% of theory. In addition, the progressive waves are shown to propagate along curved characteristics with the curvature being related to the severity of the sound speed gradient. Several eddy current heating applications are described in which propagation of acoustic waves is significantly altered by the nonuniform sound speed profile.