Reflection Characteristics of a Near-Interface Cavity in Ice at Supercritical Incidence

Abstract EN

The long-range propagation modes in an acoustic channel under ice are basically caused by supercritical incidence.

The energy distribution and transmission loss in the acoustic channel under ice are changed by a scatter in ice.

The influence of a slender cylindrical cavity near and parallel to the ice-water interface on the sound propagation is analyzed using Fourier-Bessel series and Sommerfeld-Watson transformation.

The research found that the acoustic field presents a beam in the mirror reflection direction at supercritical incidence, and the beam-width is proportional to secant of incident angle; meanwhile, the reflected coefficient is proportional to cosine of incident angle.

The reflection coefficient increases with relative depth and Helmholtz number if the incident angle is a constant.