A boundary element model for lined circular ducts with uniform flow

Peter Møller Juhl

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    A boundary element method has been developed for predicting the acoustics in a circular duct in which a uniform flow propagates. Such a model may be used to predict the performance of different liner designs for inlets of turbo fan engines, which is important for the aeronautics industry. For this application the prediction of attenuation at very high frequencies (up to ka=30) is important. However, it was found that the computational costs of a three-dimensional model would by far exceed the performance of a normal workstation. Therefore, an axisymmetric model with significantly reduced calculation time and storage requirements has been developed, and the model has been extended with a new formulation to allow for non-axisymmetric excitation. These co-called spinning modes are very important for the application to aeroacoustics. Another innovation of this work is the development of an iterative procedure that allosws an infinite duct to be modelled as a finite duct with non-reflecting boundary conditions. The numerical results are compared with the results of an analytical model for the case of an infinite circular duct with a lined section of constant impedance.
    Original languageEnglish
    Title of host publicationFourth International Congress on sound and vibration - Proceedings
    Place of PublicationAuburn, AL
    PublisherInternational Scientific Publications
    Publication date1996
    Publication statusPublished - 1996
    Event4th International Congress on Sound and Vibration - St. Petersburg, Russian Federation
    Duration: 24 Jul 199627 Jul 1996
    Conference number: 4


    Conference4th International Congress on Sound and Vibration
    Country/TerritoryRussian Federation
    CitySt. Petersburg

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