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

## 2aSA3. Calculation of the total and individual powers of vibrating finite
panel by mutual radiation impedance.

**Daiji Mikami
**

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Akio Hasegawa
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**
Toshiaki Kikuchi
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**
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*Dept. of Appl. Phys., Natl. Defense Acad. of Japan, 1-10 Hashirimizu,
Yokosuka 239, Japan
*

*
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Recently the active acoustic control technique using the controllable
secondary source has attracted much attention as an effective method to reduce
the power output from the primary source. In this technique, essential reduction
in the sound power output from the primary source is achieved by the acoustic
destructive interaction effect which is characterized by mutual radiation
impedance. In this paper, the mutual radiation resistance of two identical
rectangular panel cells (axb) simply supported in an infinite baffle is
determined from the total power output radiated to the farfield. Numerical
values of the mutual radiation resistance are given as a function of ka for
rectangular panel cells with various aspect ratios and orientation angles. The
3-D representations of individual output power from a multiplicity of panel
cells are shown for (a) even--even mode (quadrupole type), (b) even--odd mode
(dipole type), and (c) odd--odd mode (monopole type). In some 3-D plots of
odd--odd modes, for frequencies well below the critical frequency, the magnitude
of the power output from each panel cell is observed to follow the velocity
distribution of panel cells exactly.