ASA 125th Meeting Ottawa 1993 May

2aUW14. Effects of ambient noise on the scattering from cylinders and spheres.

Rebecca L. Honeycutt

Steven J. Johnson

Code 1945, Carderock Div., Naval Surface Warfare Ctr., Bethesda, MD 20084-5000

The sound scattering due to an ambient noise field, approximated by a squared cosine function, is considered for infinite rigid and elastic cylinders and rigid spheres. For the cylinders, it is assumed that the acoustic wave front is parallel to the axis of the cylinder (normally incident). For this assumption, a closed-form expression for the scattered sound field-to-incident ambient noise field (signal-to-noise) ratio is obtained not only for the cosine squared directivity, but for any arbitrary directivity that can be expressed in terms of a Fourier series. For the sphere, it is assumed that the noise is circumferentially symmetric, which leads to a closed-form expression for the signal-to-noise ratio due to a cosine-squared directivity.