Nowadays, passive mufflers are commonly used to reduce ventilation noise. However, the practical work conditions of these devices, here in aeronautic domain, involve new calculation mean for performance estimation of finite length dissipative mufflers. The previsional calculation is based on the modal theory development for cylindrical lined ducts, in the presence of a uniforn air flow. The important point of the calculation is performed by the numerical resolution of transverse boundary conditions, from the normal acoustic impedance modelling of the absorbant structure. The realised testing stand gives the fine analysis of the attenuation with an air flow, by measuring the insertion loss. This experimental study brings a validation of the theoretical tendances.
Prevision des performances de silencieux dissipatifs appliquee a la ventilation aeronautique
Die Vorhersage der Effizienz von zur Reduktion von Lüftungslärmemissionen in Flugzeugen verwendeten dissipativen Schalldämpfern
Prediction of dissipatives mufflers efficiency applied to aircraft ventilation
Acustica ; 87 , 1 ; 34-45
2001
12 Seiten, 21 Bilder, 3 Tabellen, 46 Quellen
Article (Journal)
French
TECHNOLOGIE - Vers des hélicoptères silencieux
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