Theory of the Shadow Zone Diffraction of Underwater Sound

The problem of the shadow zone diffraction of underwater sound is reduced to that of diffraction by a dark half‐plane and an asymptotic expansion of the edge wave used to calculate the transmission anomaly. This theory explains the general shape and the observed break of the transmission anomaly curve. The dependence of the calculated values on range, wavelength, and depth, is shown to agree with observations made during and after the Second World War.