On A Sound-Absorbing Coating in the form of a Layer of a Viscous Liquid with Bubbles

Abstract

The study considers the possibility of creating a broadband sound-absorbing coating for hydroacoustic measuring tanks and chambers with inertial or soundproof walls, consisting of a layer of viscous liquid with gas bubbles. The coatings are calculated using the well-known theory of sound propagation in a liquid medium with bubbles, as well as the Kramers–Kronig integral dispersion equations. It is shown that the volumetric size distribution function of bubbles should be constant over the entire range of their sizes. A viscous liquid is designed to increase bubble damping to a value on the order of unity that is optimal for coatings by adding viscous losses in the surrounding liquid to small thermal losses. Low-frequency compensating resonators are used in coatings for soundproof walls. Several examples of calculating the acoustic characteristics of coatings are given.