Development of an Energy-Based Nearfield Acoustic Holography Technique

Acoustical-based imaging techniques have found merit in determining the behavior of vibrating structures. These techniques are commonly used in numerous applications to obtain detailed noise source information and energy distributions on source surfaces. This work focuses on the continued development of the nearfield acoustical holography (NAH) approach. Source reconstructions using NAH are reliant upon accurate measurement of the pressure field at the hologram surface. For complex acoustic fields this requires fine spatial resolution and therefore demands large microphone arrays. In this paper, a technique is developed for performing NAH using energy-based measurements. Recent advancements in the area of acoustic sensing technology have made particle velocity field information more readily available. Because energy-based measurements provide directional information, a more accurate characterization of the pressure field is obtained. An analytical comparison of conventional NAH to an energy-based implementation is presented. A vibrating plate and cylinder are considered as test cases to validate the analytical results.