NOVI - Advanced functional solutions for Noise and Vibration reduction of machinery: Deliverable D1.1 Physical mechanisms of absorption and sound insulation

Seppo Uosukainen

    Research output: Book/ReportReport

    Abstract

    Absorption of acoustic wave is due to viscous and thermal losses and relaxation processes in fluid: - Absorption is emphasized near boundaries, especially in small holes, slits and narrow tubes, - Viscous losses dominate with small free space dimensions: -Perforated / microperforated plates, - Absorbing materials: "Holes" and "slits" described by fluid bulk properties (flow resistivity, porosity, tortuosity, viscous andthermal characteristic lengths). Sound transmission of a wall is due to two parallel transmission paths: - Non-resonant and resonant transmission, - Below coincidence frequency non-resonant transmission dominates except in the resonance region. With double walls above double-wall resonance, sound insulations in dBs are summed with reasonable amount of absorption in cavity if mechanical coupling is insignificant.
    Original languageEnglish
    PublisherVTT Technical Research Centre of Finland
    Number of pages45
    Publication statusPublished - 2014
    MoE publication typeD4 Published development or research report or study

    Fingerprint

    machinery
    noise reduction
    insulation
    vibration
    slits
    acoustics
    perforated plates
    fluids
    sound transmission
    tubes
    porosity
    cavities
    electrical resistivity

    Keywords

    • sound absorption
    • sound insulation
    • physical mechanisms

    Cite this

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    title = "NOVI - Advanced functional solutions for Noise and Vibration reduction of machinery: Deliverable D1.1 Physical mechanisms of absorption and sound insulation",
    abstract = "Absorption of acoustic wave is due to viscous and thermal losses and relaxation processes in fluid: - Absorption is emphasized near boundaries, especially in small holes, slits and narrow tubes, - Viscous losses dominate with small free space dimensions: -Perforated / microperforated plates, - Absorbing materials: {"}Holes{"} and {"}slits{"} described by fluid bulk properties (flow resistivity, porosity, tortuosity, viscous andthermal characteristic lengths). Sound transmission of a wall is due to two parallel transmission paths: - Non-resonant and resonant transmission, - Below coincidence frequency non-resonant transmission dominates except in the resonance region. With double walls above double-wall resonance, sound insulations in dBs are summed with reasonable amount of absorption in cavity if mechanical coupling is insignificant.",
    keywords = "sound absorption, sound insulation, physical mechanisms",
    author = "Seppo Uosukainen",
    note = "Project code: 71902",
    year = "2014",
    language = "English",
    publisher = "VTT Technical Research Centre of Finland",
    address = "Finland",

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    NOVI - Advanced functional solutions for Noise and Vibration reduction of machinery : Deliverable D1.1 Physical mechanisms of absorption and sound insulation. / Uosukainen, Seppo.

    VTT Technical Research Centre of Finland, 2014. 45 p.

    Research output: Book/ReportReport

    TY - BOOK

    T1 - NOVI - Advanced functional solutions for Noise and Vibration reduction of machinery

    T2 - Deliverable D1.1 Physical mechanisms of absorption and sound insulation

    AU - Uosukainen, Seppo

    N1 - Project code: 71902

    PY - 2014

    Y1 - 2014

    N2 - Absorption of acoustic wave is due to viscous and thermal losses and relaxation processes in fluid: - Absorption is emphasized near boundaries, especially in small holes, slits and narrow tubes, - Viscous losses dominate with small free space dimensions: -Perforated / microperforated plates, - Absorbing materials: "Holes" and "slits" described by fluid bulk properties (flow resistivity, porosity, tortuosity, viscous andthermal characteristic lengths). Sound transmission of a wall is due to two parallel transmission paths: - Non-resonant and resonant transmission, - Below coincidence frequency non-resonant transmission dominates except in the resonance region. With double walls above double-wall resonance, sound insulations in dBs are summed with reasonable amount of absorption in cavity if mechanical coupling is insignificant.

    AB - Absorption of acoustic wave is due to viscous and thermal losses and relaxation processes in fluid: - Absorption is emphasized near boundaries, especially in small holes, slits and narrow tubes, - Viscous losses dominate with small free space dimensions: -Perforated / microperforated plates, - Absorbing materials: "Holes" and "slits" described by fluid bulk properties (flow resistivity, porosity, tortuosity, viscous andthermal characteristic lengths). Sound transmission of a wall is due to two parallel transmission paths: - Non-resonant and resonant transmission, - Below coincidence frequency non-resonant transmission dominates except in the resonance region. With double walls above double-wall resonance, sound insulations in dBs are summed with reasonable amount of absorption in cavity if mechanical coupling is insignificant.

    KW - sound absorption

    KW - sound insulation

    KW - physical mechanisms

    M3 - Report

    BT - NOVI - Advanced functional solutions for Noise and Vibration reduction of machinery

    PB - VTT Technical Research Centre of Finland

    ER -