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

Akio Hasegawa

Toshiaki Kikuchi

Dept. of Appl. Phys., Natl. Defense Acad. of Japan, 1-10 Hashirimizu, Yokosuka 239, Japan

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.