Experimental Assessment of a Single-layer Near-field Acoustic Holography Method in an Enclosed Space

Planar near-field acoustic holography (PNAH) is preferably performed in anechoic spaces, since the wave-field extrapolation only holds for outgoing waves, which makes the study of certain vibro- acoustic sources a troublesome pursuit. To overcome this limitation, a number of imaging alternatives have been investigated in recent years with the use of double-layer pressure (or particle velocity) measurements, as well as of single-layer pressure and velocity measurements. Unlike these methods, our approach is to use single-layer pressure measurements and extend the PNAH method such that it is valid in the presence of a parallel reflector. In this paper we address the experimental validation of the extended PNAH formulation by means of reconstructing the pressure radiated by an omnidirectional source and exploring a few excitation frequencies. The reconstruction performance is investigated via both the free-field and the extended PNAH techniques.QC 20150828