University of Hertfordshire

Complex acoustic intensity in a duct containing an axisymmetric obstruction

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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Original languageEnglish
Title of host publication18th International Congress on Sound and Vibration 2011, ICSV 2011
Pages2232-2239
Number of pages8
Publication statusPublished - 1 Dec 2011
Event18th International Congress on Sound and Vibration 2011, ICSV 2011 - Rio de Janeiro, Brazil
Duration: 10 Jul 201114 Jul 2011

Publication series

Name18th International Congress on Sound and Vibration 2011, ICSV 2011
Volume3

Conference

Conference18th International Congress on Sound and Vibration 2011, ICSV 2011
CountryBrazil
CityRio de Janeiro
Period10/07/1114/07/11

Abstract

The measurement of acoustic intensity normally assumes that the intensity is a real quantity; however, it has been shown that intensity may also be viewed as a complex quantity in which the real (active) part is related to the magnitude of the local mean energy flow, and the imaginary (reactive) part is related to the local oscillatory transport of energy. The complex intensity field scattered by an obstruction in a circular duct is investigated here. The intensity field is assumed to be generated by a monopole source and sound is scattered by a symmetrical obstruction placed downstream of the source. The complex intensity field predictions are generated using an analytic mode matching scheme. After decomposing intensity into its active and reactive components, predictions are compared for two different obstructions at a fixed frequency. Conclusions are then drawn on the suitability of using complex intensity to recover information about obstructions in ducts.

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