Acoustic field of hydroacoustic antenna arranged near a rough surface

Abstract

The characteristics of an averaged field of a hydroacoustic antenna arranged near a penetrable ocean surface with large-scale random roughness is formulated. The model of an antenna is described as an activity cylindrical surface, restricted absolutely rigid toroid. The given model rather convincingly mirrors actual design features of modern hydroacoustical antennas. The averaged field of a hydroacoustic antenna is analyzed depending on a degree of roughness of boundary, sizes of antennas, field pattern on activity surfaces, way of the view of space and bottom penetration. It showed that, the rough surface could result into differences in distribution of averaged values of a far field of hydroacoustic antennas up to 20% in comparison with a case of free environments, the value bottom penetration, after which one of the distribution values of the mean characteristics of a near field of the antenna practically coincides appropriate values for a free environment, is established. By the given calculation and discussion, it is followed that, the ocean rough surface could be considered as the natural factor resulting in decreasing of acoustic shadow. Nevertheless, bistatic calculations of coherent field suggest useful strategies for improving in design a new model of the hydroacoustic antenna.