Verification of P-U intensity calculation
For several decades P-P probes have been used to measure sound intensity. In the last few years P-U probes have also become available. One of the advantages of these small P-U intensity probes is that they can be used in environments with high p/I indexes. Because the sound pressure and particle velocity are measured in one spot, there is no spacing (and thus bandwidth) problem, as is the case with P-P probes. The calculation of the intensity with the P-U method is fairly easy, but the characterization and implementation of the calibration values can sometimes be confusing. The accuracy of the calibration is especially important in acoustic fields with high reactivity. In this article a broadband calibration technique based on application of a spherical source is discussed. A new procedure is presented to check if the sensor responses are properly corrected. The results are compared to P-P probes, but also to a regular pressure microphone in a defined sound field (of a monopole source). Some real life structures have been used to verify intensity measurements through P-U probes.
Tijs, E.H.G., Nejade, A. and de Bree, H.E., 2009. Verification of pu intensity calculation. In NOVEM, Noise and Vibtration: Emerging Methods.