On the use of acoustical holography to locate sound sources on complex structures

Abstract

Until recently, it was extremely difficult to detect and locate far-field sound sources on complex structures. An experimental technique is presented in this paper for the identification of such sound sources on complex vibrating structures. Results are given for a preliminary investigation designed to determine the feasibility of applying a modified form of acoustical holography to the location of sound sources on ventilator fans. Such sources are identified on a three-bladed ventilator fan. Optical and computer sound source reconstructions are compared and analyzed. Results of this preliminary study are very encouraging and indicate the versatility and usefulness of this technique for modifying and controlling far-field noise radiation from complex vibrating structures.