The nearfield acoustic holography using a concentric rigid microphone array to identify cylindrical sources disturbed by environment noise

Abstract

Many nearfield acoustic holography (NAH) techniques were proposed to identify acoustical noise sources, which were usually available in the free sound field. To extend NAH to more applications in noisy environments such as factories, an NAH based on a rigid rectangle microphone array was proposed to reconstruct normal velocities of vibrating plates in the environment with disturbing noise sources recently. In this presentation, an NAH using rigid microphone array with the profiles matching the vibrating surface is proposed to identify the cylindrical surface sources. The microphone array is flush-mounted at the bottom plane, and two concentric side surfaces and two rectangular side surfaces are designed to satisfy the Neumann's boundary condition. The transfer matrix between the normal velocities of sources and measured pressure is expressed as the summation of acoustic modes of the volume within the rigid array. The disturbing waves from environments can be decomposed by the inverse patch transfer functi...