Sound source characterization of vibrating bodies by theoretical and experimental techniques

Boundary element method (BEM) is a widely used technique which has been successfully applied for many structural and acoustic problems. Sound source characterization of vibrating bodies which is the main subject of this study has been accomplished by solving Helmholtz integral equation via BEM fed by surface velocity measurements. For these operations, an available in-house computer code which enables to perform acoustic analysis of vibrating bodies in full and half space has been rewritten in MatLAB®. Additionally, a new module has been developed for this code to solve half-space acoustic problems in the presence of an impedance surface. The code is capable of post-processing operation to display sound source localizations and providing the data to be assessed by means of sound source characterization. This program which can be used for active noise control has been tested first for the theoretical acoustic sources; a dilating sphere and hemisphere. Then, as an engineering application, sound source characterization of a refrigerator has been performed. Passive noise control effect of an impedance surface under the refrigerator also has been examined. Sound measurements for the acoustic field of the refrigerator have been accomplished and compared with the numerical solutions.