THE BACK-SCATTERING OF SOUND BY HARBOR BOTTOMS AND ITS APPLICATION TO ACOUSTIC MINE HUNTING
NAVAL RESEARCH LAB WASHINGTON DC
Pagination or Media Count:
A 10- to 60-kc tiltable searchlight transducer was used to stud y back-scattering coefficients at 8 locations in Narragansett Bay. The bottom, which varied from rock through sand to mud, was examined at grazing angles from 10 deg to 90 deg. S, the scattering strengthsq yd of bottom, decreased with the grazing angle and appeared independent of frequency. At 30 deg, S varied from - 13 db for a rocky bottom to about -30 db for a muddy bottom. At 10 deg, S varied from -28 db for rock to -40 db for sand. The studies suggested that bottom roughness rather than bottom type or particle size is the important factor in determining S, and that the bottom type shown by standard analysis is only indirectly indicative of scattering. An example is given of the use of S, which was considered to be analogous to target strength, in the design of equipment.
- Acoustic Detection and Detectors
- Underwater Ordnance