An Orthogonal Line Array of Directional Class IV Flextensional Transducers

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Authors
  1. Jones, D.F.
  2. Butler, S.C.
  3. Lindberg, J.F.
Corporate Authors
Defence Research Establishment Atlantic, Dartmouth NS (CAN);Naval Undersea Warfare Center Newport Div, Newport RI (US)
Abstract
Acoustic monopoles and the princple of superposition (applied to sound pressure) are fundamental tools that can be used to construct theoretical dipole and cardioid sound sources. Strictly speaking, the size of these monopoles, and their separations when forming simple multipoles like dipole doublets, must be small compared to the wavelengths emitted. In the practical field of sonar transducer design, however, transduction devices have finite dimensions, and consequently, do not meet the basic size and separation criteria for their transmissions to be accurately described by those multipole sources. Nevertheless, there are transducers that produce good approximations to the omnidirectional, bidirectional, and unidirectional radiation patterns of monopole, dipole, and cardioid sources, respectively. One such device is the low-frequency (900 Hz) directional Class IV flextensional transducer. A single element alone can produce omnidirectional, dipole, and lef/right cardioid patterns. This unique capability provides the array designer with many options for generating directional beams, compared to arrays composed solely of omnidirectional sources. In this work, the directivity patterns of a single Class IV element and a four-element orthogonal array are presented. TRUNCATED
Keywords
Directional transducers;Acoustic performance parameters;Directivity patterns;Sonar arrays;Flextensional transducers;Flextensional projectors;Acoustic monopoles
Report Number
DREA-TM-98-232;NUWC-TM-980181 — Technical Memorandum
Date of publication
01 Nov 1998
Number of Pages
36
DSTKIM No
99-01074
CANDIS No
511023
Format(s):
Hardcopy;Document Image stored on Optical Disk

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