A review of the in‐duct method for measuring acoustic intensity and acoustic properties of materials and systems

Abstract

The decomposition theory [Seybert and Ross, J. Acoust. Soc. Am. 61, 1362–1370 (1977)] is reviewed and some new results applicable to problems in measuring acoustic intensity and acoustic properties in plane‐wave ducts are presented. Specifically, it is shown that formulations for the net acoustic intensity and for the so‐called transfer function approach of measuring acoustical impedance proceed directly from the general decomposition theory. Potential sources of signal processing and instrument errors are discussed, as are methods for instrumentation phase calibration. Experimental data showing the application of the decomposition technique to acoustic intensity and property measurement are presented.