Accession Number:

AD0770564

Title:

Utilization of an Array Matched to Individual Modes; A Computer Program to Calculate Normal Mode Propagation Using a Transmitting Array.

Descriptive Note:

Technical rept.,

Corporate Author:

NAVAL UNDERWATER SYSTEMS CENTER NEWPORT R I

Personal Author(s):

• Kanabis,William G.

Report Date:

1973-10-20

Pagination or Media Count:

52.0

Abstract:

A theoretical study to determine the optimum use of the Block Island-Fishers Island BIFI vertical transmitting array in exciting individual modes is described. Three methods of emphasizing individual modes -- phase matching, exact amplitude matching, and rough amplitude matching -- are described. The bases of these methods are derived from the basic properties of modes. Sample cases using these approaches were run through a computer program developed by the Naval Underwater Systems Center. The physical characteristics of the emplanted array and BIFI velocity profiles typical for summer and winter were assumed, and propagation loss was calculated for individual modes with the array matched in turn to modes 1 through 4. The three methods of emphasizing individual modes were evaluated for each profile and mode, and it was found that each method would successfully emphasize any desired mode and depress all others under a variety of thermal conditions. The best results would be obtained by using exact amplitude matching. Author

Descriptors:

• *SONAR ARRAYS
• *UNDERWATER SOUND
• *SOUND TRANSMISSION
• PHASE
• AMPLITUDE
• MATCHING
• COMPUTER PROGRAMS

Subject Categories:

• Computer Programming and Software
• Acoustic Detection and Detectors
• Acoustics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE