The effect of anomalous transparency of the water-air interface for a volumetric sound source

Abstract

Anomalous transparency consists in the passage at certain frequencies of the majority of a source’s radiated energy through an interface, which usually gives strong reflection. Earlier, this effect was established for low-frequency point sources located in a fluid bounded by an air medium. In the case of volumetric sources, additional scattering of waves occurs between the interface of the media and the emitter surface; and the character of the manifestation of this effect is unclear. This work, using the solution to the integral equation corresponding to a boundary value problem, examines the emission of wave energy by spherical sources of different radius and its distribution between the energy flow passing through the water-air interface into the upper half-space and the energy flow going to infinity in the lower half-space. It has been established that the size of the source has virtually no effect on the energy distribution in the low-frequency range, i.e., on the anomalous transparency effect. We also analyze how the relative dimensions of spherical sources affect the energy characteristics in the mid- and high-frequency range.