Accession Number : AD0648825

Title :   AN ANALYSIS OF UNDERWATER ACOUSTIC BACKSCATTERING.

Descriptive Note : Technical rept.,

Corporate Author : RHODE ISLAND UNIV KINGSTON DEPT OF ELECTRICAL ENGINEERING

Personal Author(s) : LeBlanc,L. R.

Report Date : AUG 1966

Pagination or Media Count : 147

Abstract : Experimental observations are conducted in a 4 x 4 x 10 feet steel tank filled with fresh water and equipped with fans for generating a wind driven statistical surface. A pulse-gate technique is employed which utilizes a single transducer. Backscatter pulse data is processed to yield backscattered power vs. incident angle and backscattered power spectral density. Two analytical models are postulated to predict backscattering as a function of surface conditions. The first model considers the surface to be made up of a finite number of random length facet scatters, each tilted at a random angle. Comparisons with the model tank data indicate that this model is unrealistic for measuring backscatter and is inadequate since it cannot predict power spectral density. Therefore, a continuous model is postulated which considers the surface to be made up of differential facets with dipole scattering patterns. Statistical averaging of the product of the backscattered signal and the time delayed signal yields the backscatter autocorrelation function. Comparisons between the literature, the models, and the model tank data are made and the useful ranges of the models are determined. (Author)

Descriptors :   (*UNDERWATER SOUND, BACKSCATTERING), STATISTICAL FUNCTIONS, SURFACES, MATHEMATICAL MODELS, NUMERICAL ANALYSIS

Subject Categories : Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE