THEORETICAL INTERACTION COMPUTATIONS FOR TRANSDUCER ARRAYS, INCLUDING THE EFFECTS OF SEVERAL DIFFERENT TYPES OF ELECTRICAL TERMINAL CONNECTIONS
NAVAL RESEARCH LAB WASHINGTON DC
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Mutual interactions between the elements of a transducer array affect the velocities, radiation loading, directivity patterns, and the internal electrical and mechanical stresses within the individual elements of a given array and element design. The effects are particularly serious and destructive where the individual elements are close packed and small in size compared to a wavelength. These interaction effects have been evaluated theoretically so as to include the electromechanical properties of each element, the array geometry, and several types of arrangements of the electrical terminals for a wavelength by wavelength square array composed of 144 individual radiators whose center frequency is 400 cps. The results of the computations are presented in terms of the theoretical velocities, radiation loading contours power radiated, electrical input impedance, and spring displacements. These results are compared for three different types of electrical terminal connections as a function of the driving frequency. Some of the more interesting results of the computations are the following. The elements located on the perimeter of the array have a much more uniform behavior with respect to frequency than the interior elements. The all-parallel connection, composed of one group of 144 elements all connected in parallel and denoted by 1.144, has the best performance at the lower frequencies, whereas the series-parallel 6.24 and the series-parallel 36.4 connections have the best performance at the high frequencies.
- Acoustic Detection and Detectors