منابع مشابه
Flow noise from spoilers in ducts.
Measurements of flow noise produced by strip spoilers in the air duct of a ventilation system and radiated from an open exhaust termination unit into a reverberation chamber have been made. The results agree with the previous work of Nelson and Morfey [J. Sound Vib. 79, 263-289 (1981)]. Prediction of flow noise produced by multiple spoilers requires the values of the ratio of the mean drag forc...
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The aim of this work is to estimate the sound power generated by a turbulent flow in a duct from the knowledge of mean quantities which can be computed with a K-e turbulence model when only the plane wave can propagate, i.e., when the characteristic frequency of the turbulence is low. It does turn out to be possible for the simplest configuration of a duct free of internal obstruction. The resu...
متن کاملInnovative noise control in ducts
The objective of this doctoral thesis is to study three different innovative noise control techniques in ducts namely: acoustic metamaterials, porous absorbers and microperforates. There has been a lot of research done on all these three topics in the context of duct acoustics. This research will assess the potential of the acoustic metamaterial technique and compare to the use of conventional ...
متن کاملNoise reduction of spiral ducts.
The paper presents noise reduction (NR) of spiral ducts as a result of computational modeling of acoustic wave propagation. Three-dimensional models were created with the finite element method in COMSOL Multiphysics version 3.3. Nine models of spiral ducts with 1-9 spiral leads were considered. Time-harmonic analysis was used to predict NR, which was shown in spectral and interval frequency ban...
متن کاملActive Acoustic Noise Control in Ducts
In this paper existing classical and advanced techniques of active acoustic noise cancellation (ANC) in ducts are collected and compared. The laboratory plant used in experience showed a linear behaviour and so the advanced techniques were not used. Due to delay on the plant, the feedback classical techniques could not be applied. The best results were obtained with the modified filtered-refere...
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ژورنال
عنوان ژورنال: The Journal of the Acoustical Society of America
سال: 2009
ISSN: 0001-4966
DOI: 10.1121/1.3127129