Finite amplitude effects in rectangular cavities with perturbed boundaries.

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Authors
Kilmer, Milo Jethroe II
Subjects
Advisors
Coppens, Alan B.
Date of Issue
1975-12
Date
December 1975
Publisher
Monterey, California. Naval Postgraduate School
Language
en_US
Abstract
The effects of boundary perturbations on finite-amplitude acoustical standing waves in rectangular, rigid-walled cavities were investigated using non-linear theory. When a high amplitude standing wave of frequency w is generated in a cavity, non-linear effects will cause a stimulation of certain normal modes whose resonance frequencies are integer multiples of w. Previous experimental observations revealed that there could be excitation of other normal modes, not belonging to the family of the driven mode, which v/as not predicted by the non-linear theory. The purpose of this research v/as to investigate the possibility that deviations from the idealized geometry could account for these observations. Of the various mechanisms possible, this work investigated the possibility of these unpredicted excitations occurring through a non-linear mechanism. The standing waves that exist in an ideal cavity must be corrected when the boundaries are irregular. The non-linear interaction between these standing waves and the corrections was studied. The ability of this interaction to excite standing waves other than those predicted in the ideal case was verified. A specific example was worked out demonstrating an unpredicted excitation, the strength of which was on the order of the magnitude of the boundary perturbation parameter.
Type
Thesis
Description
Series/Report No
Department
Physics and Chemistry
Organization
Naval Postgraduate School (U.S.)
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Distribution Statement
Approved for public release; distribution is unlimited.
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This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.
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