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- Andersson, Patrik, 1974, et al.
(author)
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The intensity potential approach for predicting sound power flow through partial enclosures
- 2011
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In: 18th International Congress on Sound and Vibration 2011, ICSV 2011, Rio de Janeiro, 10 - 14 July 2011. - 9781618392596 ; 2, s. 1261-1275
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Conference paper (peer-reviewed)abstract
- The intensity potential approach is developed for prediction of sound power flow through partial enclosures. A typical application is the prediction of radiated noise from an engine bay with respect to geometry, position and acoustical properties of screens and absorbers. The approach is based on the Helmholtz decomposition of the vector field of the time-averaged sound intensity into its irrotational and rotational components. The local power balance in a lossless medium and the Helmholtz decomposition gives a Poisson equation for the scalar intensity potential of the irrotational component only. The paper presents the approach and evaluates it by canonical examples and by comparison to measured data. It is demonstrated that the prediction of sound power through any closed surface is exact provided that the geometry and boundary conditions are correct. The comparison to experimental data shows that the method is useful in practical applications. The approach has its strength for cases with complex geometry and multiple broadband sources, but it has the potential to become more general by further development of boundary conditions. It is concluded that the intensity potential approach provides a robust prediction tool for the mid- and high-frequency range.
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| 2. |
- Thivant, Michael, et al.
(author)
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Intensity Potential Approach for Modeling High-Frequency Sound Fields
- 2011
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In: Acta Acustica united with Acustica. - 1610-1928 .- 1861-9959. ; 97:1, s. 103-114
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Journal article (peer-reviewed)abstract
- This paper proposes the intensity potential approach for prediction of high-frequency sound power radiation. The approach is based on the Helmholtz decomposition of the vector field of time-averaged sound intensity into its irrotational and rotational components. The local power balance in a lossless medium is expressed in terms of the irrotational component only, and results in the Poisson equation for a scalar intensity potential of this component only. The approach gives an exact expression for the sound power through any closed surface in terms of the irrotational component, provided that the boundary conditions are correct. The approach is evaluated by exploring the two intensity components in three canonical examples, and by comparison to measured data with special focus on directivity aspects. It is concluded that the intensity potential approach is relevant, in particular for high-frequency sound fields from multiple sources that are uncorrelated and broadbanded. However, the intensity is generally overestimated in the shadow zones and underestimated in the directly exposed regions. Further, peaks in narrow frequency bands associated with interference of waves are ignored.
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