ANGULAR DISTRIBUTION OF THE SOUND FIELD IN SHALLOW WATER

The field of a harmonic point source in layered media has certain angular distribution. Although by ray theory the angular distribution of sound field can be calculated for given receiving point, but the effect of the frequency on the angular distribution function and the sound field in shadow zone can not be calculated. In this paper, by the normal-mode theory the angular distribution of the sound field in layered media is discussed, the general expression of angular distribution function and attenuation law for directional reception are obtained. The results given above can be used for calculation of the sound field in shadow zone and they represent the influence of the frequency on the sound field. Investigating the channel of the underwater sound and the effect of the signal detection in it, by utilizing the obtained results, the optimum receiving direction can be chosen. For given medium model the numerical calculations are produced, and analysis and discussion are conducted.