Electronic Journal Technical Acoustics ISSN 1819-2408

Igor V. Grushetsky

Critical remarks on standard calculation technique of ventilation noise

language: Russian

received 26.03.2002, published 18.04.2002

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ABSTRACT

When sound energy from fan propagates along airway in ventilation system, portion of the energy is reflected back from bends, branchings, duct area reductions, open ends etc. In standard calculation technique of ventilation noise is considered that the reflected energy is fully absorbed inside the ventilation system. However in fact the reflected energy is partly consumed on reverberation field formation in ducts. Some part of reverberation field energy then radiates from openings. Standard calculation technique of ventilation noise does not take into account this part of radiation from terminal devices.

Radiation from duct open end, caused by both travelling waves from sound source and reverberation field in duct is considered in the paper. It is shown by the example that standard technique for calculation of sound power radiated from terminal devices may lead to underestimated results up to 10 dB and even more.

5 pages

Сitation: Igor V. Grushetsky. Critical remarks on standard calculation technique of ventilation noise. Electronic Journal “Technical Acoustics”, http://www.ejta.org, 2002, 2.

REFERENCES

1. Guide for architects. Noise control. СНиП II-12-77, Moscow, 1998 (In Russian).

Igor V. Grushetsky , PhD, Krylov Shipbuilding Research Institute (St. Petersburg, Russia). Scientific area - noise and vibration measurements and control. e-mail: editor(at)ejta.org