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

2pEA7. Close-packed acoustic array element interaction.

John B. Blottman III

Naval Undersea Warfare Ctr., New London Detachment, New London, CT 06320

Jean-Noel Decarpigny

Inst. Superieur d'Electron. du Nord, 59046 Lille Cedex, France

The acoustic array element interaction is an essential parameter determining transducer array behavior. It is characterized by the mutual radiation impedance. Low-frequency transducers in a volumetric array with small size constraints are subject to much larger interaction and scattering than in conventional arrays. This paper provides an overview of an investigation of the modal components of mutual radiation impedance. The in vacuo eigenmodes of a single element are determined using the ATILA finite-element method. Selection of the modal expansion terms will be based on their radiation efficiencies. Modal radiation impedances are generated using the EQI boundary integral equation method. A simple multimode equivalent circuit model of the in situ projectors, including the interaction effects, is proposed. Comparison of the results to a full finite-element model of an array is presented.