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

## 1pPA11. A new approach to compute the resultant pressure of linear array.

**Jamal Assaad
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**
Christian Bruneel
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**
Isabelle Looten
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*Dept. of OAE, IEMN, Valenciennes Univ., BP 311 Le Mont-Houy, 59304
Valenciennes, France
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In this paper, a new calculation scheme is proposed to compute the
nearfield and the farfield directivity pattern of such arrays including
interactions and without assumptions concerning the displacement field of the
transducer radiating surface. For this purpose, using the finite element method
(FEM), the farfield directivity pattern of a part of the array (2Q +1
transducers) is computed using dipolar dampers and a previous described
extrapolation algorithm [Assaad et al., J. Acoust. Soc. Am. 94, 562--573
(1993)]. This part consists of an active elementary transducer (electrically
driven) mounted between 2Q passives (electrically grounded) neighboring
transducers. Then, the radiation field of a finite phased and focused array (N
elements) can be obtained by summing up the farfield directivity patterns of the
2Q + 1 transducer sets weighted by the classical term used to take account of
the geometrical and electrical phase shifts.