Advanced equivalent source methodologies for near-field acoustic holography

The equivalent source method (ESM) based near-field acoustic holography (NAH) has been used successfully in the reconstruction of the acoustical field over arbitrarily shaped vibrating structures from measurements of the pressure field on a nearby conformal surface. In this work we study the use of the ESM dipole and a combined source representation for NAH reconstructions. Using numerically generated data from an elastic spherical shell acoustic response, the studies are focused on the correct positioning and distribution of the source points in relation to the vibrating surface, accuracy over problematic frequencies and spatial aliasing. Finally, we utilize physical data from a vibrating ship-hull structure to validate the proposed ESM reconstructions.