### ASA 130th Meeting - St. Louis, MO - 1995 Nov 27 .. Dec 01

## 2pEA6. Variation model for the radiation impedance of Class IV transducers
III.

**Harold C. Robinson
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*Naval Undersea Warfare Ctr., New London Detachment, New London, CT 06320
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Previously [H. C. Robinson and E. A. McLaughlin, J. Acoust. Soc. Am. 97,
3300(A) (1995)], the modal radiation impedance for a pair of Class IV
transducers was calculated using variational methods. This model determines
distinct self and mutual radiation impedance contributions between pairs of
surface velocity modes, including the effects of element orientation, without
requiring exact solutions to the equations of motion and boundary conditions.
However, in order to model the total radiation impedance of the transducers,
suitable methods for combining these modal impedances must be determined, which
in turn requires that some estimate of the relative importance of each modal
contribution be made. One method of determining the relative strengths is
singular value decomposition [G. W. Benthien, Naval Ocean Systems Center
Technical Report 1329, November 1989], which effectively allows one to determine
the fluid-loaded resonances of the transducer and their associated eigenvectors.
The relative magnitudes of these in-water modes will determine their importance
in the total impedance. The results of this combination will be incorporated in
a modified equivalent circuit which includes the effects of the ``banana'' mode.
Calculations using this circuit will be made to existing equivalent circuit
models as well as to experimental data.