Higher-order estimation of acoustic intensity

• Published in: The Journal of the Acoustical Society of America Vol. 141; no. 5; p. 3651
• Main Authors: Lawrence, Joseph S., Gee, Kent L., Neilsen, Tracianne B., Sommerfeldt, Scott D.
• Format: Journal Article
• Language: English
• Published: 01-05-2017
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.4987896

The phase and amplitude gradient estimator (PAGE) method [D. C. Thomas et al., J. Acoust. Soc. Am. 137, 3366-3376 (2015)] can be used to increase the bandwidth of complex acoustic intensity estimates obtained with multi-microphone probes. Despite the increased bandwidth, errors arise when using this method, which is based on linear least-squares gradients, in non-planar fields. Examples of non-planar fields include the acoustic near field of a radiating source or near a null in a standing-wave field. The PAGE method can be improved by using a Taylor expansion to obtain higher-order estimates of center pressure, pressure amplitude gradient, and phase gradient. With a sufficient number of microphones, the higher-order method is shown to improve the bandwidth of both the active and reactive intensity estimates. Additionally, this method can be used to estimate the spatial dependence of intensity across the extent of the probe. [Work supported by the National Science Foundation.]