Estimating the high frequency in-duct sound power using sound pressures at the duct wall

Antti Hynninen, M. Åbom

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

    Abstract

    When studying the acoustic wave propagation in a channel, the frequency range can be divided to the low frequency plane wave range and to the high frequency range with non-plane waves. In the low frequency range the wave propagation is one-dimensional and the governing equations are rather simple. The larger the duct the lower the frequency limit of the non-plane waves. Therefore taking into account also the three-dimensional acoustic wave propagation is important especially when considering the duct systems used in large structures, e.g., medium speed internal combustion engines (IC-engines), fans, or compressors. Harsh environment and unmovable structures restrict the use of standardized noise measuring methods. To characterize the medium speed IC-engine exhaust noise in situ, the in-duct sound pressures are measured using wall mounted transducers. Then the source sound power is estimated from the propagating sound pressures, which is the power based approach. The power based approach is only valid in frequency averaged sense and therefore the source power must be defined in one-third octave frequency bands, for example. One way to estimate the source sound power in the high frequency range, is to extend the classical plane wave formulation by defining the one-third octave frequency band weighting factors for different excitation types. The aim of this study is to define these weighting factors using finite element method (FEM) simulations of a test duct with non-reflecting terminations. The sound pressures at the duct wall were compared to the sound pressures at the duct end for randomized multi-modal excitations. From statistics, the one-third octave band weighting factors and their reliability were estimated.
    Original languageEnglish
    Title of host publicationProceeding of the 20th International Congress on Sound and Vibration 2013
    EditorsMalcolm J. Crocker, Marek Pawelczyk, Boonchoat Paosawatyanyong
    PublisherInternational Institute of Acoustics and Vibration IIAV
    Pages2553-2559
    Volume3
    ISBN (Print)978-1-62993-150-0
    Publication statusPublished - 2013
    MoE publication typeA4 Article in a conference publication
    Event20th International Congress on Sound and Vibration - Bangkok, Thailand
    Duration: 7 Jul 201311 Jul 2013

    Conference

    Conference20th International Congress on Sound and Vibration
    Abbreviated titleICSV 20
    CountryThailand
    CityBangkok
    Period7/07/1311/07/13

    Fingerprint

    sound pressure
    ducts
    estimating
    acoustics
    octaves
    frequency ranges
    wave propagation
    internal combustion engines
    plane waves
    low frequencies
    compressors
    fans
    excitation
    finite element method
    transducers
    statistics
    formulations
    estimates
    simulation

    Keywords

    • high frequency range
    • in-duct sound power
    • acoustic source characteristics

    Cite this

    Hynninen, A., & Åbom, M. (2013). Estimating the high frequency in-duct sound power using sound pressures at the duct wall. In M. J. Crocker, M. Pawelczyk, & B. Paosawatyanyong (Eds.), Proceeding of the 20th International Congress on Sound and Vibration 2013 (Vol. 3, pp. 2553-2559). International Institute of Acoustics and Vibration IIAV.
    Hynninen, Antti ; Åbom, M. / Estimating the high frequency in-duct sound power using sound pressures at the duct wall. Proceeding of the 20th International Congress on Sound and Vibration 2013. editor / Malcolm J. Crocker ; Marek Pawelczyk ; Boonchoat Paosawatyanyong. Vol. 3 International Institute of Acoustics and Vibration IIAV, 2013. pp. 2553-2559
    @inproceedings{11ceb0c0d72547bfbf6f84dd7d4963a1,
    title = "Estimating the high frequency in-duct sound power using sound pressures at the duct wall",
    abstract = "When studying the acoustic wave propagation in a channel, the frequency range can be divided to the low frequency plane wave range and to the high frequency range with non-plane waves. In the low frequency range the wave propagation is one-dimensional and the governing equations are rather simple. The larger the duct the lower the frequency limit of the non-plane waves. Therefore taking into account also the three-dimensional acoustic wave propagation is important especially when considering the duct systems used in large structures, e.g., medium speed internal combustion engines (IC-engines), fans, or compressors. Harsh environment and unmovable structures restrict the use of standardized noise measuring methods. To characterize the medium speed IC-engine exhaust noise in situ, the in-duct sound pressures are measured using wall mounted transducers. Then the source sound power is estimated from the propagating sound pressures, which is the power based approach. The power based approach is only valid in frequency averaged sense and therefore the source power must be defined in one-third octave frequency bands, for example. One way to estimate the source sound power in the high frequency range, is to extend the classical plane wave formulation by defining the one-third octave frequency band weighting factors for different excitation types. The aim of this study is to define these weighting factors using finite element method (FEM) simulations of a test duct with non-reflecting terminations. The sound pressures at the duct wall were compared to the sound pressures at the duct end for randomized multi-modal excitations. From statistics, the one-third octave band weighting factors and their reliability were estimated.",
    keywords = "high frequency range, in-duct sound power, acoustic source characteristics",
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    Hynninen, A & Åbom, M 2013, Estimating the high frequency in-duct sound power using sound pressures at the duct wall. in MJ Crocker, M Pawelczyk & B Paosawatyanyong (eds), Proceeding of the 20th International Congress on Sound and Vibration 2013. vol. 3, International Institute of Acoustics and Vibration IIAV, pp. 2553-2559, 20th International Congress on Sound and Vibration, Bangkok, Thailand, 7/07/13.

    Estimating the high frequency in-duct sound power using sound pressures at the duct wall. / Hynninen, Antti; Åbom, M.

    Proceeding of the 20th International Congress on Sound and Vibration 2013. ed. / Malcolm J. Crocker; Marek Pawelczyk; Boonchoat Paosawatyanyong. Vol. 3 International Institute of Acoustics and Vibration IIAV, 2013. p. 2553-2559.

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

    TY - GEN

    T1 - Estimating the high frequency in-duct sound power using sound pressures at the duct wall

    AU - Hynninen, Antti

    AU - Åbom, M.

    N1 - Project: 82112

    PY - 2013

    Y1 - 2013

    N2 - When studying the acoustic wave propagation in a channel, the frequency range can be divided to the low frequency plane wave range and to the high frequency range with non-plane waves. In the low frequency range the wave propagation is one-dimensional and the governing equations are rather simple. The larger the duct the lower the frequency limit of the non-plane waves. Therefore taking into account also the three-dimensional acoustic wave propagation is important especially when considering the duct systems used in large structures, e.g., medium speed internal combustion engines (IC-engines), fans, or compressors. Harsh environment and unmovable structures restrict the use of standardized noise measuring methods. To characterize the medium speed IC-engine exhaust noise in situ, the in-duct sound pressures are measured using wall mounted transducers. Then the source sound power is estimated from the propagating sound pressures, which is the power based approach. The power based approach is only valid in frequency averaged sense and therefore the source power must be defined in one-third octave frequency bands, for example. One way to estimate the source sound power in the high frequency range, is to extend the classical plane wave formulation by defining the one-third octave frequency band weighting factors for different excitation types. The aim of this study is to define these weighting factors using finite element method (FEM) simulations of a test duct with non-reflecting terminations. The sound pressures at the duct wall were compared to the sound pressures at the duct end for randomized multi-modal excitations. From statistics, the one-third octave band weighting factors and their reliability were estimated.

    AB - When studying the acoustic wave propagation in a channel, the frequency range can be divided to the low frequency plane wave range and to the high frequency range with non-plane waves. In the low frequency range the wave propagation is one-dimensional and the governing equations are rather simple. The larger the duct the lower the frequency limit of the non-plane waves. Therefore taking into account also the three-dimensional acoustic wave propagation is important especially when considering the duct systems used in large structures, e.g., medium speed internal combustion engines (IC-engines), fans, or compressors. Harsh environment and unmovable structures restrict the use of standardized noise measuring methods. To characterize the medium speed IC-engine exhaust noise in situ, the in-duct sound pressures are measured using wall mounted transducers. Then the source sound power is estimated from the propagating sound pressures, which is the power based approach. The power based approach is only valid in frequency averaged sense and therefore the source power must be defined in one-third octave frequency bands, for example. One way to estimate the source sound power in the high frequency range, is to extend the classical plane wave formulation by defining the one-third octave frequency band weighting factors for different excitation types. The aim of this study is to define these weighting factors using finite element method (FEM) simulations of a test duct with non-reflecting terminations. The sound pressures at the duct wall were compared to the sound pressures at the duct end for randomized multi-modal excitations. From statistics, the one-third octave band weighting factors and their reliability were estimated.

    KW - high frequency range

    KW - in-duct sound power

    KW - acoustic source characteristics

    M3 - Conference article in proceedings

    SN - 978-1-62993-150-0

    VL - 3

    SP - 2553

    EP - 2559

    BT - Proceeding of the 20th International Congress on Sound and Vibration 2013

    A2 - Crocker, Malcolm J.

    A2 - Pawelczyk, Marek

    A2 - Paosawatyanyong, Boonchoat

    PB - International Institute of Acoustics and Vibration IIAV

    ER -

    Hynninen A, Åbom M. Estimating the high frequency in-duct sound power using sound pressures at the duct wall. In Crocker MJ, Pawelczyk M, Paosawatyanyong B, editors, Proceeding of the 20th International Congress on Sound and Vibration 2013. Vol. 3. International Institute of Acoustics and Vibration IIAV. 2013. p. 2553-2559