Analysis of Liquid-Core Cylindrical Acoustic Waveguides Embedded in Solid Media

Abstract

The propagation of elastic waves in liquid-core cylindrical acoustic waveguides is studied. The model analyzed represents a liquid-filled tube embedded inside a solid medium. The frequency equations are derived, and expressions for the displacement components and stress components are presented. Phase velocities of wave motions at low-frequency and high-frequency limits and cutoff conditions for all propagation modes are provided. Wave motions of three example waveguides constructed of different materials are calculated. The results show that the material properties of the waveguide and its surrounding medium determine the existence and the asymptotic limits of the guided wave motions. Displacement distributions and geometry effects are also studied, and the results reveal that, by selecting proper material combination for the liquid core and the solid tube, the waveguide can help to transmit signals in materials with high acoustic attenuation. Results also show that there are two propagation branches (the first branch of the longitudinal mode