Vertical Directionality of Low-Frequency Wind Noise and Vertical Array Optimization for the Wind Noise Limit

摘要

Normal mode-based noise modeling is applied to investigate the structure and the environment dependence of vertical wind noise directionality and the optimal design of vertical arrays for detection in a wind noise background, using, as examples, two deep-water sites, one in the North Atlantic and the other in the North Pacific. The contributions to the noise directionality of the overhead (direct-path), surface-interacting, and sediment- interacting components of the noise field are examined through analysis of the vertical noise response of a reference aperture. Environmental influences investigated include the effects of (1) the wind noise source distribution in range, and (2) the acoustic propagation environment, including water-column depth and sound speed, sediment attenuation, and sea surface roughness. Spatial configurations of vertical arrays with arbitrary phone spacing are optimized by simulated annealing to maximize a measure of the mean array The beam patterns of the optimized arrays adapt to the noise directionality by trading off beamwidth, sidelobe levels, and single-element signal-to-noise ratio.