THE BACK-SCATTERING OF SOUND BY HARBOR BOTTOMS AND ITS APPLICATION TO ACOUSTIC MINE HUNTING
Abstract
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 strength/sq 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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1953
- Accession Number
- AD0016696
Entities
People
- R. J. Urick
Organizations
- United States Naval Research Laboratory