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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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",
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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 -