Flow-induced noise calculations for vector hydrophones in towed arrays

Abstract

The purpose of this study is to develop an integrated analytical method of flow-induced noise for vector hydrophones in towed arrays and discuss the parameters that influence flow-induced noise character. Based on Carpenter turbulent boundary layer pressure fluctuation model for slender cylinder, the power spectra and cross power spectra of acoustic pressure and particle velocity of flow-induced noise, are deduced by utilizing the wavenumber-frequency spectral analysis. It is shown that the flow-induced noise is determined by the towed speed, the size of both vector hydrophones and elastomer tube, the material parameters of elastomer tube and so on. In addition, the condition that cylindrical vector hydrophones are distributed non-axially in elastomer tube is also taken into account. Considering the influence of the axis-off distance on acoustic pressure, axial particle velocity and radial particle velocity, a set of numerical results show that the influence of the axis-off distance on the high-frequency component of the acoustic pressure and axial particle velocity is greater than that on the low-frequency component. The radial particle velocity is influenced by the axis-off distance within the full frequency range. The impact of the axis-off distance on the particle velocity is far greater than that on acoustic pressure.