Internal wave-induced azimuthal fluctuations in the acoustic field

Abstract

In describing the effects of internal waves on acoustic normal modes excited by a time-harmonic point source, all previous descriptions have neglected the existence of azimuthal fluctuations in the acoustic field. This study compares this azimuthally symmetric case with the case where azimuthal fluctuations in the acoustic field are taken into account. Although azimuthal variations enhance the randomization of interference effects so that different depth modes decorrelate more quickly in range, this enhancement is generally small. The mean energy flux vector (j) becomes radial at long ranges; the vertical components of (j) decay somewhat more quickly with range when azimuthal fluctuations are considered than when they are neglected. [Work supported by Office of Naval Research.]