Research on the construction of spatial quasi-self-bending beams in acoustic waveguides

Abstract

This paper proposes a method of constructing spatial quasi-self-bending beams in a waveguide. The method is based on the fact that when the energy of a sound wave in a waveguide with an absorbing liquid scatterer is totally transmitted, the sound wave will bypass the scatterer. By artificially designing the shape of the scatterer in the acoustic waveguide, the scatterer boundary is regarded as the propagation trajectory; the corresponding totally transmitted sound field is calculated, and the spatial quasi self-bending beam is constructed with the scatterer boundary as the trajectory. In addition, the same method is used to construct a shallow water sound-channel-axis highly-focusing beam, and the obtained quasi-self-bending beam can bend automatically during propagation. More importantly, these self-bending beams retain the self-healing property, that is, even if their main peaks are truncated, the acoustic wave will automatically reconstruct the main peaks after propagating for a certain distance. Due to the self-bending and self-healing properties, these beams have potential applications in strong anti-interference acoustic communication. The obtained sound-channel-axis highly-focusing beam is highly concentrated near the sound channel axis during propagation, and has no interaction with the sea surface and seabed, so it can be used for ultra-long distance acoustic communication. The method described in this paper is also suitable for exploring more special spatial beams.