ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06
2pEA10. Variational model for the radiation impedance of class IV
transducers II.
Harold C. Robinson
Elizabeth A. McLaughlin
Naval Undersea Warfare Ctr., New London Detachment, New London, CT 06320
In a previous paper [H. C. Robinson and E. A. McLaughlin, 3318(A)
(1994)], the variational method of determining modal radiation impedances was
applied to a pair of class IV transducers. The self- and mutual radiation
impedances for the quadrupole, octopole, and monopole modes were presented.
This paper extends the analysis to include the effects of other asymmetric
modes of the class IV. The in-vacuo mode description of the transducer's
surface velocity will be improved by using three-dimensional mode shapes. The
trial functions describing the surface pressure are modified as well. Changes
in the impedance characteristics for the symmetric modes due to this improved
transducer description will be shown. The characteristics of the nonsymmetric
modal impedances are compared to those of the symmetric modes as a function of
dimensionless major axis ka and dimensionless separation distance kd. Suitable
methods for combining these modal impedances into a total radiation impedance
for the transducer will be presented. The effect of relative orientation of the
transducers on the radiation impedance is investigated. The results will be
compared to equivalent circuit models and experimental data. [This work was
sponsored by the Office of Naval Research.]