ASA 127th Meeting M.I.T. 1994 June 6-10

2aEA7. Comparison of the coupling between two flexural underwater transducers computed using the finite-element method and the Pritchard approximation.

Jean-Marc Cortambert

Steven R. Baker

Physics Department, Naval Postgraduate School, Monterey, CA 93943

Understanding the coupling between transducers in the array becomes fundamental to proper beam forming in the active sonar array. The paper presents the study of two-dimensional, axisymmetrical closely spaced, class V flexural disks. The analysis was performed by using a finite-element program, ATILA, developed to compute easily the near-field radiated pressure between the two double trilaminar disks. Their self and mutual impedance are computed and compared to those obtained by the Pritchard formula. The distance between the two transducers is optimized to point out multiple scattering when it occurs. The goal of the study is to correlate the limit of the validity of the Pritchard formula with the distortion of the near-field pressure between the transducers. The results are compared with the impedance measurement of the flexural disk and the pressure field near the transducers. [Work supported by the French Delegation Generale pour l'Armement and the Naval Postgraduate School.] [sup a)]Permanent address: DCN Toulon, CERDSM, BP77 Toulon 83 000, France.