ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06

2pUW3. Investigation of three-dimensional bathymetric refraction using laboratory scale modeling.

Stewart A. L. Glegg

Anthony LaVigne

Joseph M. Riley

Ctr. For Acoust. & Vib., Florida Atlantic Univ., Dept. of Ocean Eng., Boca Raton, FL 33431

Experimental measurements have been carried out to identify the effect of bathymetry on three-dimensional underwater sound propagation. The measurements have been conducted over a 1/10 000th scale model of the Santa Lucia Escarpment off the coast of California. Experiments measured the bearing error obtained in locating a source with a horizontal line array using a phase-wave beamformer. The results of this experiment demonstrated significant variations in the measured bearing error. Differences in the detected bearing of the variations beamformer and the actual source location were as large as 18 deg, with the magnitude of these errors being a function of bearing line and source frequency. An analytical solution of the acoustic field in a shear supporting wedge using the method of images has been used to approximate the results of the bearing error experiment. Comparison of experiment and theory shows the same effects with bearing errors of the same magnitude. [Work supported by ONR.]