Sound Absorber and Silencer

Sound Absorber and Silencer

1. Sound absorber

  • porous absorbers (mineral wool, melamine foams, hollow metal sphere structures, open-porous asphalts, fills, etc.)
    • characteristic values of materials (measuring method, airflow resistivity, porosity, tortuosity, …)
    • acoustic design of sound absorbers right at the wall as well as at a distance to the wall
    • covers of absorbers (perforated plates, …)
    • acoustic design of sound absorbing curtains
  • micro-perforated sound absorbers
  • plate-shaped oscillators and perforated plate-shaped oscillators
  • Helmholtz resonators
  • resonator with dimension equal to fourth of wave length
  • combined absorbers

2. Silencers and mufflers

  • absorption muffler
    • types of construction
    • effectiveness (frequency response, limiting effect, …)
    • fields of application
    • approximate solution of Piening
    • flow noise
    • pressure drop
    • exact solution
  • reflection muffler
    • types of construction
    • effectiveness
    • fields of application
    • insertion loss at an abrupt change of cross section
    • insertion loss of a chamber
  • resonance muffler
    • types of construction
    • effectiveness
    • fields of application

3. Computational design of silencers and mufflers and evaluation by means of acoustic measurements

  • design of sound absorbers with analysis software
  • acoustic evaluation of porous materials by measurement of airflow resistance with airflow resistivity meter AcoustiFlow®
  • acoustic design of silencers and mufflers by means of silencer software AcoustiCalc®
  • measurement of spectral transmission loss of silencers and mufflers in the test setup for mufflers AcoustiTube® HighTemp

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