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CISDOC database

Document ID (ISN)60291
CIS number 93-1012
Year 1991
Convention or series no. Notes scientifiques et techniques 86
Author(s) ThomÚ J.P.
Title Contribution to the study of acoustic transmission through a slit of finite length. Application to the study of noise leakage from industrial machine enclosures
Original title Contribution Ó l'Útude de la transmission acoustique Ó travers une fente de longueur finie. Application Ó l'Útude des fuites acoustiques sur les encoffrements de machines industrielles [in French]
Bibliographic information Institut national de recherche et de sÚcuritÚ, 30 rue Olivier-Noyer, 75680 Paris Cedex 14, France, June 1991. 258p. Illus. Bibl.ref.
Abstract Thesis. Enclosures are often used in industry to reduce machine noise. They are rarely in one piece, and often allow noise leakage that reduces their effectiveness. Two analytical models were studied and applied to the calculation of the noise attenuation index of a wall with a rectangular slit. A parametric study showed the influence of aperture geometry and incident wave frequency. The spatial distribution of the acoustic energy transmitted by the slit is described. A numerical model enables calculation of the directivity of radiation in the cases of normal and oblique incidence. The latter case is also described by a stationary phase integral at high frequencies; a relation is established between the principal axis of radiation and the angle of incidence. These models were validated on a test bed, and the importance of aperture geometry on the quantity and spatial distribution of transmitted energy.
Descriptors (primary) noise; sound transmission; mathematical models; acoustic enclosure
Descriptors (secondary) noise measurement; thesis
Document type E - Books, reports, proceedings
Country / State or ProvinceFrance
Subject(s) Noise, hearing and vibration
Broad subject area(s) Physical hazards
Browse category(ies) Noise