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Anomalous transparency of water-air interface for low-frequency sound

Oleg A. Godin
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Abstract

Sound transmission through water-air interface is normally weak because of a strong mass density contrast. Here we show that the transparency of the interface increases dramatically at low frequencies. Rather counterintuitively, almost all acoustic energy emitted by a sufficiently shallow monopole source under water is predicted to be radiated into atmosphere. Physically, increased transparency at lower frequencies is due to the increasing role of inhomogeneous waves and a destructive interference of direct and surface-reflected waves under water. The phenomenon of anomalous transparency has significant implications for acoustic communication across the water-air interface, generation of ambient noise, and detection of underwater explosions.

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Oleg A. Godin. 2006-09-04. Anomalous transparency of water-air interface for low-frequency sound. https://doi.org/10.1103/physrevlett.97.164301

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